Katalin Karikó — Forging the mRNA Revolution (#147)

58 min read
Katalin Karikó — Forging the mRNA Revolution (#147)

Katalin Karikó is a Hungarian-American biochemist. She is one of the inventors of mRNA technology.


JOE WALKER: Katalin Karikó, welcome to the podcast.


WALKER: Thank you, for everything. So today I have three goals. I firstly want people to hear your story, because it's unique and inspiring. Secondly, I want to talk about mRNA technology, because it's fascinating and important. And thirdly, I want to talk about some metascientific issues as well.

But let's start with your background. So you were born in Hungary. Tell me what life was like growing up there in the Soviet era.

KARIKÓ: "Soviet era" — you don't feel that. You have your family, you have your neighbours, your school, your local environment. You just go to school, you do whatever you are doing as kids and in the family.

I had a very happy childhood. We had a small house. We had two rooms, but we used just one during the winter because it was one you could afford to heat up. And we had a big garden. We had animals like pigs and chickens. We had a vegetable garden.

I have an older sister, she's three years older, and we had our little garden. We could plant the seeds ourselves, and we attended those gardens. We had flower gardens. So it was like Eden there. I was very happy growing up.

My father was a butcher. My mother, she worked at home and then later she was a bookkeeper. We had a simple life. We didn't have running water; we had to run to the street to get drinking water which we carried home. And we did not have refrigerators; we put everything in the well to cool it down. But everybody in the neighbourhood was like that. We didn't have a television set, in at least the first ten years in my life. It was a little adobe house with a reed roof. And so I went to school and I enjoyed it. I was very happy.

WALKER: I didn't realise this until I started researching for this conversation, but the word stress wasn't applied to humans until the 1930s. Previously it was only used by physicists. And it was first applied to humans by the Hungarian endocrinologist Hans Selye.

KARIKÓ: Selye.

WALKER: Selye. Thank you. And in high school you read a book about stress by Hans Selye. Can you tell me how that influenced your thinking? Why was it so impactful?

KARIKÓ: Indeed, we actually wrote a letter to him. And he responded and we got so excited. Because he was born in Hungary, his book about stress was translated to Hungarian, and so in the '60s, you could read his book.

We discussed it in biology class. So we did understand that stress can kill you — but only how you perceive it. So you have to learn to handle the stress.

And what he said also in his book was that without stress life is meaningless. You wouldn't get up this morning if you don't have this anticipation, excitement, that we will talk today.

So you need that kind of happiness… This is also stress, but it is a good stress… And how you would, when you are kicked out of your job, see the goodness of it.

But you have to learn, and it is a practice. So we practise and we talk in the school about how we can focus on things that we can do. That's the problem with people: they focus things that they cannot change. It was important that the conversation has to be about what I can do, not blaming others. And so it was very helpful.

WALKER: Without reading that book, would you have been as good at handling stress? I feel like your personality is very optimistic, naturally.

KARIKÓ: Yeah. I wouldn't be here, I wouldn't be talking with you.

WALKER: Really?

KARIKÓ: I would not reach that, because it was so critical. What I can see, even today, is that people are comparing themselves to the others immediately. Don't do that! Don't worry about that other person who works less and gets promoted and gets hired. You cannot change that. But the people paying attention to this, they get distracted and they are not focusing what they can change — doing the research. And they are blaming. They blame their children, their husband, wife, neighbours, somebody. And then you cannot change those people. They wish that they would do this and that. No. You have to always end every conversation in your mind with “What can I do?” So that's very helpful.

And if people would learn this, they would live a much better life. For example, the grudge that people have against somebody. So many people ask how I feel now that I can tell those people who were not nice to me. I mean, I thank people who were not nice to me, because without them, I wouldn't be here. Because hardship and those things are forming your personality. Much better than if somebody prepared yours, and you just have to walk an easy way.

So if you struggle you learn many things. Also, people who were not nice to me made me work harder with what I have. And then that's how you have to process. So even in… Actually in school — in high school we are talking about reading this book — my high school teacher told me — he didn't like me — and he told me after I graduated to the highest mark, he said that he knows somebody at the university and he will make sure that I will not be accepted.

At first you could see that, "Oh, this is mean and bad news." But if you say, “Okay. How do I perceive it?" That's important. "I perceive that I have to work harder, so I have to be the number one. So no question about that. I will be accepted.” If he says: “I will arrange that you will be accepted”, I sit back and work less hard. So you have to see it as: “Okay, he made me work harder.” And then you also learn, every time, you learn that not everybody's rooting for me. And that was your lesson of the life there — so not everybody wants you to succeed. And you have to think about that. You have to practise, to think: “Okay, what did I learn from it?” Because even the meanest person to tell you anything, you learn: “I won't do that, I won't say that to anybody else because it's hurtful.” So I learn, and then you move on. That's the simple philosophy. I don't know, maybe there is such philosophy that exists. But if you live your life then you are so much happier.

WALKER: Yeah, it sounds a little bit like Stoicism which is a bit of a podcast cliche, but I won't go into that. But it's a beautiful perspective. Why was that teacher so mean to you? Was he just a bad guy or did you do something to piss him off?

KARIKÓ: There are always people that… They don't like if somebody is too successful. Because even in elementary school I already competed nationally in Hungary in a biology competition.

WALKER: And came third. In the whole country.

KARIKÓ: Yeah, I was third best in the country. It was a whole-week competition. In high school I was writing different essays. I always was very inspired and competitive, and not everybody likes that. And some people have power that they can crush you and they try to use it. But you just don't have to think about too much.

WALKER: So if that book was so important to you, I'm wondering why you didn't go to study psychology or something like that?

KARIKÓ: I like biology. And so it is also very important in science that you focus on something, try to solve the problem. And I know that we might talk later about what is in science. But what I could see is that, as long as I am focusing on that science part and try to solve it. Me and the problem and then solving it, and that's how it is. But then you want to have more people, so you apply for more money, grants and other things, and then you are moving away, because if you get promoted, you get even more positions to get more colleagues and more money. And then finally the goal is this promotion to get a bigger team. And then what was originally the goal to understand something, became a tool to reach that goal, to get this promotion and tenure position and whatnot. But there, you are not in control because somebody will decide. I think that many people who gave up their job during the pandemic, those who were in tenured position, what they realised was that: “Oh, I am just the manager, I am in the desk writing grants, writing papers and those others are having fun in the lab,” and they miss that.

WALKER: Yeah, I have lots of questions about that, which I'll ask you a bit later. So you became interested in science at school. You did exceptionally well in that week-long biology competition you mentioned. And then you graduate high school, you go to university, you biology at university. And then you start your PhD programme in 1978, and you start work on RNA that same year. But that kind of happened by chance, right? Could you tell me that story?

KARIKÓ: Yes. I might mention also to get into university was very difficult because the whole country… They invited for the oral exams 300 and invited 30 and then accepted 15. So it was very difficult. And because my parents had just elementary school education, I get a chance during the summer to participate at the university in a programme for the underprivileged children. So that it was not the first time in my life I entered a university, but during the summer. And it was very important the university initiated this kind of programme for the children.

WALKER: Because your dad did six years of elementary, your mom did eight years.

KARIKÓ: Yes. And so nobody was high school educated in our family. And so it was important, this kind of action. At the university, I went to Szeged — it is a southern part of Hungary, this university city — because the Biological Research Centre was planned to be built there and started or opened in 1972. So in 1973 I decided that I will go to this city because there is the Biological Research Centre. And that was my dream to work at that place. When I started at the university, we had an early morning, like seven o'clock, start in the morning, and then eight o'clock we had so many different classes. Even Saturday we had classes. It was like analytical chemistry, physical chemistry, biochemistry and all of this microbiology… We learn everything. It is not like here in the United States.

But then I went also to the research centre, the Biological Research Centre, as a student, and I ended up in the lipid team, which seems like a boring thing. And then I spent a summer actually in a fishery institute collecting fat from fish to identify when we feed them with different chow, different material, what their fat looks like.

And so this working with lipids... What happened is one day, two colleagues from this biochemistry section of this Biological Research Centre wanted to make liposome and they needed phospholipids and they came to our lipid team for help. And then I participated when we isolated this phospholipid. We needed phospholipid, but were behind the Iron Curtain and that fraction which you can buy for ten Deutsche Mark, it was not available for us. So we had to isolate. We looked at an old recipe, 1942, how to isolate this phospholipid from cow brain. So it came in handy that my father was a butcher and when I looked at the brain I wouldn't say “Oh, this is disgusting.” And we did like five days. When different fraction we took away, with using different kind of organic solvent, acetone, ether, chloroform and so on. And we get this fraction of this phospholipid. I was so excited. And I work later on this with [inaudbile], and we worked to make liposomes and we put DNA in it and delivered it to the cells. They did this at the end of the '70s, when they delivered a viral particle to a cell, which otherwise you couldn't infect because there were no receptors on it. And they did so many interesting things. It, for me, was very exciting. And just one day, Yanu Thomas walked in, and then my supervisor mentioned that "Katy is finishing and she wants to get her PhD." And Yanu said: “Oh, okay. I am in the RNA lab, she can come and work with me.” That's how it was. So then, "Okay, RNA."

WALKER: When you got interested in RNA, PCR hadn't been discovered yet. That wasn't discovered until the mid 1980s (and maybe in a moment you can explain what PCR is). But without PCR you couldn't create synthetic RNA. Why were you so excited about RNA at that stage before synthetic RNA had been created?

KARIKÓ: I started to work in the RNA lab in 1978 and the prior year, '77, Ian Care in London discovered that there is a short RNA molecule which might be responsible for the interferon mediated antiviral effect. The interferon is a cytokine which was known that interferes with the viral replication. And Yanu came actually from the pharmaceutical industry to this research centre and he thought that we need an antiviral compound. He had connections to the industry and they sponsored our research so we could develop an antiviral compound. This had three nucleotides containing short RNA molecules linked with two prime-five prime, which is an unusual linkage.

We had to make it enzymatically, we made it chemically. I also set up the antiviral testing lab there. And it is interesting that, even later in my life, I always work with colleagues who are not experts in what I had to do. Everybody here was an organic chemist, and I was the biologist. I had to set up the assays, had to understand making this small molecule biologically and later on life also. Everybody was expert in a different field.

And maybe this is how invention happens, and novelty, because you educate each other and then you come up with something that you wouldn't, as individuals, think about.

So anyway, this RNA molecule was an exciting thing and we made good progress.

The problem was the delivery. In animal study it was not feasible. We couldn't wrap up this small molecule to deliver it inside the cell. And we lost our support from the industry.

But when you work with RNA at the end of the '70s and beginning of the '80s, you learn how to label, different enzymes you work with. And it was just a lot of knowledge you gather with this and it stays with you. This molecule, which makes this two prime-five prime molecule, this is an enzyme we have in our bodies. This is also important for COVID. They identified that those children who get seriously sick, they had a problem, they did not have enough of that enzyme. They had a mutation in it. I follow all of the fields I ever worked in, to see what is going on today. And so I can see that those important molecules and understanding is very critical.

But anyway, I enjoyed working with these RNA molecules. And of course when I learned that I cannot work further in this institute, I tried to find another place where they are working with these molecules. First in Europe, but they couldn't get a stipend as a post doc. And then finally ended up here in Philadelphia — Professor [inaudible] was also interested to work in this two prime-five prime linked antiviral molecule.

WALKER: I'll come back to your move to the US. But I guess I have another question about what you were thinking during your PhD programme. So you were originally interested in using RNA to develop therapies. Had you begun thinking about vaccines at that stage?

KARIKÓ: No, I was not that visionary. I was just excited about learning virology. I mean every time I read this book David Baltimore wrote and I said, “Oh my God, these viruses are so smart.” Of course it is just because of evolution, not that they figure out how to get around our immune system. But because they evolved this way. But I learned a lot of biology. I learned with working with RNA. That was exciting for me.

WALKER: So tell me about the big move to America in 1985.

KARIKÓ: Yes. So at my 30th birthday I learned that I have to leave. I have six months left and then I have to leave the institute, and I have six months to find another job.

This was my first time when I was kicked out. And so again, every time I say that — several times later it happened — if I wouldn't be kicked out that many times, I wouldn't be here. Because it is important that you don't take it personally, don't take it as somebody is deciding that you are a loser. What is important is what you do next. So that's how America came.

And it was not easy because in '85, we are still in a communist Hungary. And to prevent defection, they only allow my family, my two and a half years old daughter, my husband and me, to move to America with $50 for Susan, my daughter, $50 for my husband and me. They said, “Ask your employer for money.” So with $100, a small family would leave Hungary and come America. The next day, how we will live? They tried this way to limit movement. And so that's how we started.

WALKER: And you actually came over with a little more cash than that because you were able to sell your car on the black market. How does that work?

KARIKÓ: Yeah, I mean, we had a Russian car, which we could sell officially. We just have to change the money of the black market because there were students from Arabic countries that I could exchange with. Actually, he didn't have dollars, he had pounds. And so I exchanged and we get something — 1,000 dollars; 800 pounds. It was like $1,200 equivalent. In Hungary, the Hungarian currency was not convertible and you couldn't go and purchase freely from your foreign Hungarian currency to dollars. And if somebody would give you money, foreign currency, like a dollar, you had to go to the bank and give it to them and they will give you whatever Hungarian currency. You are not allowed to have [foreign currency]. It was against the law. But we have to live somehow. And so this $1,000 was like a lot of money.

Later it turned out that we had to hide it in Susan’s teddy bear, because it was smuggled. She smuggled it out.

WALKER: We can blame Susan.

KARIKÓ: Yeah, Susan smuggled the money. Other Hungarians also send me letters and emails that say: “Where did they hide?” Everybody had to come out with some extra money. You just cannot come with a family to America with $100.

WALKER: Yeah. So did you sew it into the teddy bear?

KARIKÓ: So I put it in, I wrapped it up and then I stitched it back. And then we watched her at the airport to make sure...

WALKER: "Don't let go of that bear!"

KARIKÓ: "Don't leave that bear there.”

WALKER: Did she know the money was in it or was she too young?

KARIKÓ: No, she was two and a half years old.

WALKER: Oh wow. So at this point, I actually want to kind of digress from your story and talk a little bit about the science, because I think people will need some basic understanding to then follow the rest of the discoveries that happen over the next few decades from when you land in America. And maybe, I don't know, Katy… By the way, people in America say Katy [as in matey], but in Hungary, you would say Katy [as in putty], right?

KARIKÓ: Yes, correct.

WALKER: I'll say Katy. So maybe a nice framework to kind of frame this Microbiology 101 section of the conversation would be Jim Watson's central dogma of molecular biology, which is that DNA makes RNA makes protein. And the information is unidirectional, so it flows in that direction only. DNA and proteins never actually meet, and that's why they need messenger RNA, which is a particular type of RNA. There are actually other types of RNA. I apologise because I know this is so basic, but maybe it would be helpful if we just quickly go through each of those things. So firstly, could you explain DNA?

KARIKÓ: DNA is a storage of information in our body. Every cell in our bodies has it and all free living organisms and even viruses can have DNA. It contains information and is composed four basic nucleosides and the order of it defines what kind of protein it is coding for. And the DNA is quite stable. You can isolate DNA from dinosaurs; there's still sequences out there. So this is a storage of the information.

WALKER: So when palaeontologists excavate dinosaur bones, sometimes they can recover the DNA but they can never recover the RNA which is very unstable. It self-destructs. So talk a little bit about that.

KARIKÓ: So there is a very small difference between DNA and RNA. The major one is that the DNA is double-stranded, the RNA is single-stranded. But beside that, the chemical composition is just hydroxyl, and extra hydroxyl is present on the sugar part of RNA which makes it very labile. You don't even need an enzyme to cut it up. If you just store it in a room temperature, sooner or later your RNA is degraded.

This is its role also in the body. And that was the reason, actually from the '50s, they already were looking for this messenger RNA, and they couldn't find it because it was so labile. So in 1961, in two papers published in Nature, the word labile was in the title in both of those papers. Labile.

WALKER: And the messenger RNA is, as we said, a particular type of RNA. You also have tRNA and then you have…

KARIKÓ: Ribosomal RNA. Actually 80-90% of our RNA in our body is ribosomal, and they are part of the protein synthesis machinery.

So there is DNA. The process of making an RNA is transcription and those are performed by RNA polymerases. Enzymes which can polymerase makes RNA. And the RNA goes to the ribosomes — and this is the protein synthesis factory. And then the tRNAs, the transfer RNAs carrying the amino acid, are reading the sequence and they putting one amino acid after the other as the sequence dictates and you have the protein.

WALKER: So proteins are made of amino acid and DNA, and RNA, is made of nucleic acid.

KARIKÓ: Very good.

WALKER: Thank you. Proteins are, as you said, manufactured in the ribosomes, which sit in a particular part of the cytoplasm in the cell.

KARIKÓ: It can…

WALKER: ...float around.

KARIKÓ: A lot of places, it can be.

WALKER: Okay. And DNA is located only in the nucleus.

KARIKÓ: If it is eukaryotic cells, yes, it is in the nucleus.

WALKER: Yeah. And correct me if I'm wrong, but there are upwards of about 30,000 types of protein in our cells.

KARIKÓ: I don't know.

WALKER: But there are many.


WALKER: Yeah, I guess the key point is that protein is like the functional unit of the cell.

KARIKÓ: Yes, the different proteins, because those proteins could be enzymes, generate lipids and other components of our bodies.

WALKER: So over the years people have tried to create therapies at the beginning and the end of that chain. So we've had gene-based therapies focused on DNA. I guess Genentech pioneered protein-based therapies from the 1980s.

KARIKÓ: I have to say that even before, because 100 years ago insulin was introduced. That was the protein replacement because there were the type-1 diabetes patients, and those proteins were isolated at the beginning. So a hundred years ago they isolated from animal tissue or different sources and then this is what they used.

And in 1982 come the recombinant proteins. When they could make human protein by bacteria or different cell factories — those were recombinant protein. And that started in '82.

WALKER: Okay, I see. So people had tried things with DNA-based therapies, protein-based therapies. But RNA-based therapies were very difficult, maybe even considered impossible, when you were working on RNA.

KARIKÓ: Even the DNA started… 1990 started the Human Genome Project.


KARIKÓ: And then they started to identify the genes and the mutation in it and identify that as responsible for a certain disease. The thought was in the 1990s that, “Oh, we just deliver the correct genes and everything will be fine.” So that was the focus on, I mean Human Genome Project was 13 years, 1990 [to 2003]. You remember Bill Clinton announced that we know the human genome.

And so they tried to focus on that but it was not easy. They thought that we need permanent changes back to normal. Interestingly, maybe in these days it seems now that the promise of the gene therapy based on DNA actually may be fulfilled by RNA. Because the CRISPR-Cas9 technology came and you could change the genome with very simple enzymes which will recognise certain area of the genes. And that is delivered as mRNA. It is critical that it will be short-lived and just make the change and everything disappears. So it's an exciting time, what we have now.

WALKER: Yeah. Okay, so to return to your story. So you arrive in the US in 1985 and you're still obviously really excited about RNA. When did you become excited about mRNA in particular?

KARIKÓ: At Temple University, I worked three years, and we worked with different kind of RNA there. Actually we did a human trial together with Hahnemann University and we used double-stranded RNA to treat HIV patients. Because you know that in 1986 that was a major viral problem, that infection. And then was no assay, no test, it was very difficult that time.

But then we used double-stranded RNA. And then I worked one year at Bethesda. I did very basic molecular biology there. And there, I was reading day and night, because my family lived in Philadelphia and I worked in Bethesda.

And I entertained this thought that people try to use antisense RNA, and I said why not use the sense RNA and deliver it as therapy. And I start to read about that and what can be done. And it came in very handy.

One day this guy walked in and he said he has this lipofectin they just developed and it can deliver nucleic acid easily to the cell. And then I said, “Oh, that's what I need,” because this liposome, what I did in Hungary, was very tedious to [inaudible] and very complicated and very fragile.

And so I thought, “Oh, that's it, I need this lipofectin.” Then I applied for a new job at the University of Pennsylvania. And then I proposed to my colleague who hired me that we will use messenger RNA and we will do it because I was reading that we can make mRNA. Because we were in '89, and in '84-85 two publications came out from Harvard University. And Douglas Melton and Paul Krieg, they described that you can use phage RNA polymerase, which has a very high fidelity, very efficient, very simple way to generate RNA. And so I said “Okay, we are set.”

WALKER: Love it. So in '89 you got the position at the University of Pennsylvania. So you wanted to make RNA, put it into a cell, instruct the cell to make proteins that it wouldn't otherwise make. And you set up an experiment with a machine called a gamma counter to detect the protein.

KARIKÓ: So I went to Cardiology. So my colleague, Eliot Barnathan, he was going to see patients and catheterising and so on. And then I was trying to educate him about RNA, and he tried to educate me about blood vessels and coagulation and what problem we have there, what problem we have to solve. And so his interest was in this urokinase receptors which can bind to a molecule — that is used to solve the clots, which unintentionally form in our blood vessels and cause heart attack. And then if we would have more of these molecules there, let's say, when they do bypass surgeries — because that's what they also did there... And so, they have a blood vessel in hand and then they try to insert, and then we can have some RNA put through on it. And what this RNA should be is this urokinase receptor, that would be beneficial. So I cloned and made RNA for urokinase receptor. And my colleague made radiolabeled urokinase and to test whether this mRNA — which codes for urokinase — are delivered to the cell, whether they make functional receptors. And to measure it, we had to use this radioactive material and to see whether it binds or not.

Why it is so critical, this urokinase receptor? Because this protein had to be so much modified, so many things had to happen to be functional. And voila, you delivered the RNA and somehow the cell knew what to do. Put there all of these sugars in it which needed process the other end of the carboxy terminal end of this protein and linked and it was functional.

We were watching this gamma counter that printed out slowly this result and we could see that okay, it works. So at that time we thought that, "Oh okay, we can use X-Vivo," like on a blood vessel, on cells, deliver RNA and get beneficial protein overexpressed for a short period of time.

WALKER: So that's when you first realised you could use mRNA to get cells to create protein. After that you were in the — I'm sort of exaggerating here — but in the wilderness for many years. You suffered a series of career setbacks. Could you talk about some of those stories?

KARIKÓ: So we were making this progress, and I have to say, from 1989 in the first two years I worked at University of Pennsylvania, every month I wrote a grant to get money to establish myself. I had a faculty position as a research assistant professor, which is a non-tenured position, but I could have my own lab. But I didn't get any of those.

I tried to propose the RNA, how I would use circular RNA actually. In these days they think it is a new thing. In '92 or '93, I already had grant — which was rejected. I proposed [circular RNA], and I did a circular RNA anyway.

So I was working hard to do the experiments, generating more data. But it was not sufficient. They were critical that RNA is labile, it wouldn't be useful and I don't have enough data. Sometimes they questioned that I had enough knowledge to do these experiments. I was always listening because, Seyle "What can I do?" Not that they should accept my proposal, otherwise you would think they are dumb. No, they don't understand how great the idea is. If I conclude that they don't understand, I have to say “Yes, because maybe I did not explain it well," and so I improve my writing, my colleagues look at there and did more experiments.

But at the university there was a rule that if in five years you do not establish yourself in a faculty, you don't get money, then you have to be promoted or kicked out and demoted, removed from the faculty. And that's what happened to me in 1995.

WALKER: And that was a difficult time for a couple of other reasons. You were diagnosed with cancer. Your husband got stuck in Hungary with his Visa.

KARIKÓ: I had lumps in my breast. And then, at the same time when we went to the hospital, my husband had to go back for his green card. And we didn't read carefully and two days later he left. I was here and then he couldn't return because what happened is that when I was in H-Visa, he was still working and paid the tax and they looked at that. He was not supposed to work. And so if we hadn't paid the tax, they wouldn't see it, but we were always honest. And so he was stuck in Hungary for five months. He came back in May. He left in January.

We just purchased a house, we had to pay the mortgage. And it was like I just couldn't rest. I had to find a new job, and it was a very difficult time. One of the students who, prior, was a student in the lab — a medical student — by that time he worked as a resident in Neurosurgery. His name is David Langer. He convinced the chairman that Neurosurgery needs a molecular biologist. It is just so unbelievable he could convince him but he said, “Okay”. And they gave me a laboratory, they gave me a salary and that's how for 17 years I worked on this bench there.

WALKER: Because I was surprised reading some of your papers, it has you as being in Penn's Department of Neurosurgery. Yeah, even the famous 2005 paper.

KARIKÓ: Yes. 17 years I worked there. Again, with David Langer, we tried to solve different problems and now I am working with somebody who's going there every day, operating on a patient and comes back with what kind of problem he is facing, what he can do, and what I can do, and what we can do together.

So maybe innovation is coming this way. Sometimes you have a huge lab and you can investigate a problem in many different directions and then you advance knowledge, science. But also that you are talking to maybe just a person and you talk to each other and then realise together what you can accomplish.

WALKER: So that sounds like an extremely difficult period.

KARIKÓ: Yes, people usually say, “Katy, you suffered so much.”

I have to say that I was always very happy. In the laboratory, I was at the bench. All the way. When I was 58 years old, I still did my own experiments. I cultured the bacteria, isolated plasmid, made the RNA, cultured the cells, transfected, measured. I did every part. Put the gels, a lot of gels, and analysed the data. Came home, reading, writing, doing all of these things. And I felt that I was in full control. I was in the laboratory, I know what to do. I was reading something in the evening at home, I realised: “Oh, maybe let's provide an explanation of what I am seeing,” and, “Okay, I can do it. Oh, I can do it.” And the next day I went in and then I was just doing that experiment. And so it is very empowering. And the discovery that many technical problems I am solving, it is a success.

I didn't get the grants — with the basic R01 grant in the United States you can establish a laboratory — but I had a lot of happiness. These discoveries and full control over the experiments is very empowering and exciting, and you have an understanding of how things are. And then you are reading articles — not like when you start to read an article and after the second sentence you think, “What I am doing? Why I am doing this?” — but you are looking for something and that is so exciting, this hunt. Because you have a hunch that something is happening.

WALKER: Have you ever calculated what percentage of your grant applications were successful?

KARIKÓ: No. It has to be zero point zero something, because I had one grant when we established the company after our discoveries. The first grant we submitted was for a small business grant to the US government, NIH. Then we received that grant. That was the only time I was PI on a grant.

WALKER: So, fast-forwarding to 1998. This was a big turning point or moment in your career, because you're standing at a Xerox machine (photocopier) at the University of Pennsylvania and you meet Drew Weissman. Can you tell me that story?

KARIKÓ: Yeah, 1997 or 1998, something like that. We don't remember either, whether it was ‘97 or ‘98, I don't know.

It is critical because from 2002, I never went to the Xerox machine. I downloaded everything digitally. So thank God that progress was not that great in certain fields because otherwise I would never have met him. Because of course, it is much easier to download papers digitally.

But at that time I had Science, Nature paid for. And then I went there, Xeroxing and archiving the papers, and the system set up for that and so on.

Then I noticed this new guy on the floor there: he's also occupying that Xerox machine, my favourite one. And in ‘97, ‘98, I was already working in Neurosurgery, but they didn't have their Xerox machine. So I still went back to the Department of Medicine, which is just four floors up. Probably I knew the password for the Xerox machine, and I used that.

So I started to talk to this new guy. I asked him what he was doing, and of course I always brag about what I am doing and so on. But he's a much more quiet person. And he told me that he was working at Anthony Fauci's lab, which told me nothing because Anthony Fauci was not in the television set like in the last two years or prior to that. And he was working in HIV research and he wanted to develop a vaccine, a prophylactic or a therapeutic — I’d never even heard of a therapeutic vaccine.

That's when we started actually educating each other, because I told that I am making RNA and I can do anything. And then he said he would be interested to test out the mRNA as a vaccine and I make the RNA.

Meanwhile, I learned the immunology from Drew Weissman. When I learned, we understood how our immune system works to recognise that something is foreign. “Oh no.” Drew told me: “Oh, bovine serum albumin the you would inject into your body is doing nothing.” He said that you need a dangerous signal. That what was understood. You need an adjuvant, you need to tell something to your immune system: “Hey, that's dangerous, you have to make an immune response against it.”

So that's how we slowly educated — or sometimes not that slowly educated — each other. I learned immunology, and he learned RNA. I made the RNA and he was very happy.

In 2000, we published about this HIV specific protein that we delivered to the human dendritic cells, which was discovered not long before that. And this is the most professional human immune cells with which he could make culture and test out, and this he delivered. And then everything was great because not only you delivered the protein generated from this mRNA, but also this activated everything he wanted. And a lot of inflammatory molecules were made.

That made me sad when I realised he was happy with all of these activities. But I was not happy because I did not want to have any inflammatory molecules. My goal was to make therapeutic protein-coding RNA.

Then we started to think together, “Why is the RNA I am making different from what is inside the cell — or not different at all?”

The reason why it's so inflammatory is because we are putting something from outside the immune cells and this RNA is not supposed to be outside the cell. That suggested the idea that “Oh, we should test out… We should isolate RNA from our human cells,” and see that when we put it on these special immune cells, human dendritic cells, whether they respond the same way (when we put the RNA made in the tube on them).

We never thought that we would identify something that is not immunogenic. At that point we expected that all of them would generate an immune response.

We isolated transfer RNA and ribosomal RNA, bacteria, different bacterial RNA, and then we just put them on the cells, and then we found that this transfer RNA did not induce any immune response. And that made us think that, “Could it be that this transfer RNA, which is very well known, contains the most modified nucleosides, maybe makes them nonimmunogenic?” So that was the thought generated. Of course the next question immediately was how the hell will we prove that? How will we make RNA containing nucleoside modification?

WALKER: So to summarise, you and Drew meet in ‘97, ‘98, whenever it was. And that kind of represents the marriage of immunology with mRNA. So this is the most important collaboration in your career. This is the collaboration that leads to the mRNA-based vaccines. And the big problem or obstacle that you and Drew are trying to overcome is the immune response problem. So the body basically rejects the synthetic mRNA. It's immunogenic: causes inflammation. And so you're trying to work out how to basically mask the synthetic mRNA so that the cells accept it.

KARIKÓ: We just wanted to understand where this immune response is coming from. We didn't set out with a goal to make a non-immunogenic RNA. We had no idea that such a thing exists. We just wanted to understand: “Is the RNA I make synthetically any different from what is inside the cell?” And the way to prove that is to isolate it out from the cell, make one in the tube, put it on the cell and see: did they respond the same way? And of course we found that most of the RNA did induce the immune response. In our body, our RNA is inside the cell. But when you have an injury, it comes out — you also get an inflammatory reaction from that.

WALKER: So after a few experiments, you and Drew discover that all you had to do was modify the mRNA. And the way to do that was by just adding one molecule called pseudouridine. Can you tell me about this discovery?

KARIKÓ: So, when we discovered that a transfer RNA — which has a heavily modified number of nucleoside present; like 25% of the nucleotide in a tRNA is modified — we thought that we have to make mRNA to see that whether we can have a translatable product which is not immunogenic.

We already knew at that point there are more than 100 modifications that exist in RNA and we didn't know which one is important in the tRNA. Do we need all? Or one? And the enzymes, which incorporate it, which makes the changes, are not known. So we just couldn't call up a company to send that enzyme.

We thought that we have to maybe purchase these building blocks and try to see whether we can incorporate. And we insisted on just purchasing a kind of modification which is naturally present in the human body, and nothing foreign — just a kind of modification present in the human body, concentrated.

Anyway, we purchased ten (they were all that was available), and five of them incorporated. So we could make RNA. The other five: not incorporated.

Then, when we looked at these RNAs containing five different modifications, we found that as long as the uridine was changed in this mRNA then it was not inflammatory. And what we found is that when pseudouridine was present, we could have ten times more protein from that RNA. So it was like icing on the cake.

WALKER: Right. The double whammy. Not only was it non inflammatory...

KARIKÓ: …But now we have so much more protein.

WALKER: Right. That's cool. So there was a question I really wanted to ask which was whether you had a causal hypothesis as to whether pseudouridine would work or whether you were just kind of spraying and praying and you discovered it by trial and error.

KARIKÓ: You have to understand that when you have RNA from the DNA, there is hydrogen bonding sequence information, the sequence order; you have hydrogen bonding needed. When you have an RNA, and it’s read by the tRNA, again you have a certain interaction between the messenger RNA and the tRNA. And then, you have to make sure that when we made the mRNA, those which are required to make this interaction are not blocked by different modifications.

So, it was obvious that only those instances for which we couldn't synthesise RNA, the reason was because this bonding couldn't form. We expected that all of them we could make could be translatable. And so it was expected that all of them would be translated. It was a surprise that we couldn't make any protein from two of them.

You have to understand that we changed all of the nucleosides in those mRNA. Naturally, actually, we learned ten years later that our messenger RNA also has pseudouridine. We just didn't know at that time. In 2002, 2003, we didn't know. 2014, they described it and they could identify it, because the pseudouridine and the uridine is actually the same molecular weight. The base in both of them is Uracil. Only the link, how the base is linked to the sugar, is different. So very similar, and they couldn't identify it because the weight was the same.

WALKER: I see. Okay. So this discovery was published in a paper in 2005, which is now a very famous paper. But the reaction from the scientific community was lukewarm.

KARIKÓ: When we first wanted to publish in Nature, we also included the translation. But then we organised… because they rejected it immediately, they said that it was an “incremental improvement”. And I had to look up the word “incremental”. I didn't know. I started to learn English when I was 18 and “incremental” was not part of it.

We took out the translation part so then we just had the immunological part. And the translation part was published in 2008, because by that time we had generated data in animals. We demonstrated that in animals also it's not immunogenic, the RNA; we demonstrated it can be translated there. So we put more data on it.

But in 2005, Drew, who is a very quiet person, told me that our telephone will ring and people will call us. But nobody called. He said that we will be invited to give talks and other things. But we got two invitations, in 2006.

WALKER: Right. And then fast-forwarding: 2013, you give a lecture. You meet the founder and CEO of BioNTech at the lecture. He offers you a job. You start at BioNTech. Not long after that, so about 2015, Pfizer and BioNTech partner to try and make…

KARIKÓ: 2018.

WALKER: Oh right. Okay. Yes, sorry. So, 2018 they signed the partnership to collaborate on making an mRNA-based flu vaccine. And were you directly working on that mRNA based flu vaccine?

KARIKÓ: Yes, on a collaboration with Pfizer and signing the agreement here in Pearl River in New York State. We were there, and also because I presented the modified nucleoside there, because my colleagues here — Norbert Pardi, Drew Weissman — were already working on formulation and getting better and better data. So I was involved and tried to help that project.

WALKER: And the way that partnership works is BioNTech does the science and Pfizer does the manufacturing and distribution.

KARIKÓ: You know, it's a collaboration science. It was that we will handle the production and whatnot. So we met the scientists there. They did experiments, also, animal experiments. So it was that way.

WALKER: I have some specific questions about how mRNA technology works. But actually before those, I wanted to ask about this incredible partnership with Drew. So I've heard Drew say in some interviews I was watching in preparation for this, that it was your interaction, the chemistry you had, that made the project work, and without each other's knowledge the technology might have taken another 5, 10 years to develop, if at all. And so your interaction is what helped push the field forward. I'm really interested in the idea of partnerships. There are obviously some famous scientific partnerships that came before yours with Drew. Watson and Crick comes to mind. I was wondering… So you and Drew couldn't get funding in the early days of your partnership. So you couldn't add more people to the team. Was that a blessing rather than a curse? Because it meant that you could only work together as a pair and maybe there's something more productive about pairs.

KARIKÓ: We can’t play the movie to see what would happen if we had money, what would happen if they don't kick me out from cardiology, or so on. We don't know if more people worked on it whether we could advance faster and better, or whether it would be more distraction or a different direction.

But when we looked at the data, Drew just gets so excited, as I was, and we cut each other's words. Whereas he's very quiet but then: “Maybe this is this way, we should do that”. And also when we were working, he kept submitting grants for using it as a vaccine. I was submitting grants for therapeutic purposes. And in the middle of the night I would just email him something and he would respond because at three o’clock he was still up and he's also working. And you feel that we were trying to do something together.

Immediately, when we looked at the data, we saw that modification is important. If we don't have modification we have a lot of interferon in use. He as a physician thinks differently, and he thinks, “Oh, maybe the lupus patients don't have a modification.” And then he immediately goes out, gets samples from lupus patients and we try to isolate back the RNA, see whether their RNA is not modified.

So his mind is in a different direction, and I am a basic scientist. I add that part to the story. And you have to respect your colleagues the same way. And then come together to develop something and get excited. It is important.

Although we never work even in the same department, not in the same building. Neighbouring building. But we did great work together.

WALKER: Some specific questions about how mRNA technology works. Could you just explain how mRNA vaccines work?

KARIKÓ: So, mRNA vaccines. The mRNA, we did not invent it. Nature invented it. And actually it was invented for pathogens. The [corona]virus has 29 different protein encoding sequences. Now we are selecting just one, and actually the virus also contains mRNA. So we just select one of the 29 protein coding sequences, and this we are using as a vaccine.

Why? Because it codes for a protein which is on the surface of the virus and that could be recognised by the immune system and can neutralise it, eliminate that kind of virus. So actually, instead of old times when they tried to attenuate the virus, we are eliminating all others and just selecting the critical RNA part which can code for the protein that can be neutralised. I don't know whether it was good. Too complicated.

WALKER: No, that was perfect. Thank you. I guess this is more of a historical or sociological question about the community of researchers, but something that's been puzzling me is, if we go back to that central dogma of molecular biology — DNA makes RNA makes protein —, you've essentially got three kind of playgrounds there to experiment with for therapeutics. Although I'm sure that's simplifying it, because it's not as if the opportunities within each of those three are necessarily equal. But it's fair to say that at least one of the big playgrounds is RNA.

Moreover, there's something very intuitive about using mRNA to develop vaccines because conceptually it's almost like the mirror image of how a virus works, because the virus hijacks cells using mRNA and then replicates. And so I get that the immune response problem seemed really difficult, maybe intractable. But the history of science is just filled with problems that seemed intractable. And so maybe there was only like a really small chance of solving that problem. But given that the payoff was so large, the positive benefits that could come from it were so large, surely in expected value terms (if you multiply that very small probability by the massive positive benefit), it was still worth dedicating a lot of research to. So what's the answer here? Why were people so dismissive, so sceptical? Was it that academia and the funding system distorted the incentives of other scientists? Or did RNA just genuinely seem like a delusional thing to be working on? Why were people so sceptical? I don't understand.

KARIKÓ: Vaccine sceptic or sceptical about the mRNA possibility to explore?

WALKER: The mRNA possibility to explore.

KARIKÓ: I have to say, Joe, that recently there have been more papers about me than I have ever published. And they are trying to identify why I never got the money, why [funding bodies] didn't give this proposal money.

One interesting thing was published about that. There is a “centre” where the money, the fame, is; most likely your proposal gets funded because it’s on the most favourable topic. Maybe today, RNA is [most favourable]. If you are working with mRNA, maybe that's the centre there.

And then there are people in the periphery. There is no fame, there is no money, no nothing there. The only thing in the periphery is freedom. You can do what you like to do, what you feel is important.

Here’s what a proposal is: why they should give me money. And they should question that. “She came from university nobody knew about.” “She never had a mentor who was famous.”

And somehow it gravitates always to the same people, same circle. They get published there, they get the money. And that's another explanation: I was not famous enough or didn't have anybody who would support me in a way that somebody that’s a famous and well-established scientist stands behind you and says, “Oh, look at this, it’s good.”

You know, our [2005] paper had to be discovered by scientists at Harvard. In 2011, they published. That's when people started to pay attention — when they used it to generate induced pluripotent cells, stem cells.

WALKER: So the idea is maybe difficult to evaluate or it seems a bit crazy. And so then people need to, I guess, look at your background or your pedigree to decide whether to award a grant.

KARIKÓ: One thing is, for example, I was not faculty. And the other thing is that those who are evaluating, already have big labs to run, to write the papers and they have like, I don't know, ten grants. And they read. They have limited time.

And then they see something which is similar to what they are doing, those people who evaluate, who already got money… That's why you always get the same kind of field. The money. Because [evaluators] read quickly and say, “Oh, that's interesting. It makes sense.” They immediately understand, because they are in that field. And if something comes out so unusual, they can stand behind just one proposal — and that would be the one which they understand quickly, because it is similar to what they are doing.

WALKER: I do have some questions about how we can improve science, but as I said, I'll save those to the end because I want to come back to the object-level questions about mRNA technology. Something that I've been thinking about which I think, as you know, is very important, is the delivery mechanism. And so we use polar lipid nanoparticles or lipid nanoparticles to deliver the mRNA into the cell. And they're quite a crude delivery mechanism. So I was wondering whether there are ways of delivering mRNA without polar lipid nanoparticles. Can we get delivery mechanisms to be more targeted? Could you use antibodies which are more direct? Or GalNAcs which don't hurt the liver?

KARIKÓ: So the lipid nanoparticles actually contain four different components, lipids. And one of the components is actually the adjuvant for the vaccine. So they are not inert just wrapping material, they have function also. And not only lipid nanoparticles, there are others… Lipoplexes are used, for example, for cancer therapy, for vaccines, as well as for tolerance induction. Then you don't have these kinds of components, you have different kinds of lipids in them.

And when you deliver IV, injected, it goes to the spleen or, in the other case, lipid nanoparticles go to the liver, or if it is injected locally, intramuscularly, most of the time macrophages and other immune cells will pick it up, because that's their role to pick up things. And of course you can deliver an RNA in targeted way because if it is delivered to the wound, you just put it on the surface. Of course you try to reach certain cell types or certain organs, and then for this you need some targeting. And of course there are publications about using antibodies to target those particles, but you cannot freeze them together, or you have to create them at the bedside, because you have the particle frozen and then you put the antibody — if you freeze the antibody they mix up and then they won't function. So there are technical hurdles there.

But you can also put it on the surface. They did actually with a ligand, which you use to target a cell which has the receptor, and when the ligand reaches the receptor, it takes in the whole cargo together with the RNA.

There are different tricks that people are using, and this is a very intensive field right now, that people try to improve delivery methods to reach certain places. One of them is the bone marrow, because editing there for certain diseases, like sickle cell anaemia or others, is critical to reach [bone marrow], or for treating HIV patients.

WALKER: Which new potential delivery method are you most excited about?

KARIKÓ: The targeted one, a different way to target, is very important and very intensively used right now. I am also interested to see when it is not used as a vaccine, as a therapeutic. And some therapeutics when it codes for editing enzymes, it will be used for gene therapy, or used like what I also worked on at BioNTech, when the messenger RNA codes for cytokines and we inject it to tumours. And then making a cold tumour hot, so that all of the immune cells will run there and recognise which kind of signal, which kind of epitope they have to look for, and when they circulate, they can find already distantly located tumours and they can eliminate that. This is a clinical trial ongoing with Sanofi.

WALKER: Once you've got messenger RNA that's been delivered into a ribosome, that's been turned into a protein, that's really only like the beginning of the story, because you still need to consider the protein's tertiary structure. And, as you know Katy, if the protein is folded in a certain way, it may or may not be able to interact with a particular receptor. And so post translational modifications are really important in regulating a protein's function. Certain amino acids can have a phosphate group added to them — that can have a big effect on protein. It can become linear rather than bent. Sugars can also be added and affect the protein's function. So the way in which the protein is decorated is important to how it goes on to function.

And so my question is: Once you've decided — say with the Coronavirus vaccine — once you've decided to deliver the spike protein into the cells, how do you think about engineering it so that the spike protein would be folded in the correct way and presented to the cells in the correct way? Because obviously if it wasn't folded in the right way, maybe our immune system wouldn't have produced antibodies that were the exact right fit for the virus.

KARIKÓ: I was not participating in generating the Corona vaccine, but the cells know how to do this kind of decoration. It is interesting what you are saying because at the beginning… So when our first project was using Erythropoietin, we tried to show the biological effect. Erythropoietin is made by kidney cells, but of course we injected the mRNA to the muscle, or sub-q, or to the skin. A protein is made and the erythropoietin, half of the weight is sugar and it can function. Only those sugars are there. And interestingly, it didn't matter where we injected and where this mRNA was translated, we always had functional protein. So the cells, even if they normally not making that kind of protein, they know what to do. There are very unique cases where really you need a certain chaperone present in the cell to make it default properly but it's very rare. Any cell can do. And when they were made for the vaccines, of course in that case, a big advantage was already knowing certain amino acid change is required to have the conformation. So that was incorporated in the vaccines. And when you inject, the cell knows what to do, because certain amino acid presence will say what kind of sugar, what kind of modification had to happen there. And that's why… Because we are mammalian and it was a problem when they tried to make human protein in the bacteria, because they don't glycosylate and you couldn't make certain recombinant protein in the bacteria.

And when we are talking about therapy, you mentioned that sometimes you can deliver the protein, deliver the RNA or DNA, you have to understand that the protein therapy only works for extracellular protein. If you want a protein in your nuclei — and that's what should be there —, if you just inject that protein, it never finds the way. How would they know where to go?

But when you deliver the mRNA, it can have the signal on it to where to go. So it had to be translated inside the cell. So that opens up that with RNA, not just that you can replace most of this protein therapy, which is very expensive, because you had to figure out how to modify the protein and purify, and that's why all of the recombinant protein product antibodies are very expensive.

With the RNA you don't need that. You just deliver the RNA, the cell will know how to decorate, how to do those things. You don't have to purify, but you can also generate intracellular protein, which will work inside the cell. Of course, for that one you have to reach that specific cell, those neurons or that heart cell or whatever cells, and that's the challenge. But otherwise for targeting, if you have just extracellular protein, you don't need target, any cell can do.

WALKER: I see. I guess that actually raises one of the benefits of RNA-based therapies. It can do both intra and extracellular stuff.

KARIKÓ: Yes, protein, you can generate both.

WALKER: Yeah, yeah. I know you didn't work directly on the COVID vaccines, but I guess I just had some like coming to COVID now, some questions about that.

So COVID comes around in 2020. Scientists sequenced the coronavirus's genome in January. Pfizer and BioNTech and Moderna vaccines enter clinical testing in April of 2020, so very shortly thereafter. The vaccines start going into the arms of patients in December 2020. I guess there may be a couple of reasons why this could happen so rapidly. One is just like the nature of mRNA technology itself, but the other is that you'd already been working on that mRNA-based flu vaccine from about 2018. And so there was almost like a template that they could just redeploy for COVID.

KARIKÓ: Correct.

So, I guess a few questions — and feel free to pass on any of these if you don't feel like you're well positioned to answer them. So why do vaccines normally take so long to be developed?

KARIKÓ: You can develop a vaccine, but if there is no virus around, it is difficult to evaluate. So that's what happened several times already. They develop a vaccine, and you have to test. And then if the virus disappears, then you cannot measure how good your vaccine is. And you know, at the beginning, as the vaccine was developed, the virus was passaging, passaging, until it was less dangerous. And it still could generate an immune response. So it was technically such. Later, where viral protein was delivered, which was generated as recombinant protein together with some kind of adjuvant, also generating recombinant protein, again, this technically was not easy. I am not an expert on this one, definitely. But that's what I can see. That major reason.

WALKER: So there are currently about three variants of COVID circulating. There are like two previous variants which are functionally extinct. If there are three variants circulating, does that mean you can only get sick three times at the moment?

KARIKÓ: So I have to say that when I have any kind of vaccine related questions, I ask Drew Weissman, and he said that if we wouldn't have new variants, we would be fine. And he also told me that none of the vaccines are 100% protective. You don't get different kinds of infection because the virus is not around.

But if it were around, you might get [infected] even if you were vaccinated. So, this is just thinking that, “Oh, we don't get any of these diseases.” Yeah, because the pathogen is not around.

Definitely, when a messenger RNA coding for this spike protein is injected, and repeatedly they found that the repertoire of antibodies increases. So different parts of the spike protein are recognised by antibodies and you generate those. So this is why even if you get a new variant it is not deadly for those who got vaccinated already.

WALKER: Why don't the current mRNA COVID vaccines seem to be infection blocking?

KARIKÓ: Again, I mentioned that I'm not an expert. My understanding is that when you have in your blood a high level of antibodies, because you just got vaccinated, then actually in your mucus and also in the milk — people send me pictures showing that in their milk — they can see, detect antibodies. So that you will have antibodies in other areas. And then when the antibodies’ level drops, then you might have less in your mucus or in the nose and other places to capture it. But again, better if you don't use these things, because I am not an expert and I don't try to pretend, I don't know the viruses. I left BioNTech because I want to concentrate on something which excited me for many years.

WALKER: Yeah, fair enough. Okay, so we’ll finish on COVID. I really want to ask you about meta-scientific issues, so thinking about how we can improve how science is done. And we've spoken about some of the issues and how they kind of intersect with your own personal story. Generally there are a lot of problems, like one of them, which is relevant here, is that very talented scientists need just a lot of luck. They have to be in the right university at the right time to get grants and set themselves up with a faculty position. And then there's like a chicken and egg problem where you need grants to get the faculty position but then the faculty position helps with the grants. You have to convince your seniors that you'll be able to bring grants in. So those are all challenges I'd like to discuss.

But actually firstly, Katy, I'd like to ask: So you're someone very remarkable in that you just kept persisting, you maintained your optimism, you didn't let things affect you. It's probably not even accurate to say you didn't let them affect you, you tried to reinterpret them positively and use them to drive you. Did you see any colleagues though who just weren't as tenacious and who simply gave up? Generally, how many talented scientists do you think we lose because they just feel defeated by the system and the politics of science?

KARIKÓ: Yes, definitely. So it is not easy to be a scientist, but other fields are similar. I have to say, one issue is I am a woman. If in 1982 in Hungary there were not be rules that affordable, high quality childcare, when my daughter was four months old and I could leave her there, I wouldn't be a scientist because I couldn't afford it, I had to stay home. And then if you stay home for two years, then you are so out of knowledge that it is almost impossible to catch up. So there are many things. You didn't mention the women issue. You can see that there are more female students at the universities. But the number of those that have faculty positions is dropping relative to the men. When they have children at the same time they should push their career, it is difficult. But even for men it would be good if affordable childcare were there, because they also take part in childcare and they have responsibility to put bread on the table. And they have to give up sometimes their field.

Interestingly, in Drew Weissman's lab was a student and he wanted to be a scientist but when he realised what happened to me — and in the medical field you have to bring in the money; it's not like in other fields; in medical science as a scientist you have to cover your salary — and he decided that he will be MD, PhD. Because as a doctor he can still function and have a family. So that's the difficulties in our field to be a scientist. And definitely men will give up because if they don't get enough money, then they cannot support their family.

And I have to say that I don't have hobbies. My hobby is science, so that's also easy that I don't get too much money as a salary, but that's enough. We can get by.

But how could we improve? How could we see that something is a good idea? It is difficult because there could be great ideas, but I don't have expertise on it — just like when we talked about viruses; I did a lot of work with viruses, but still I wouldn't say that I am expert on it to judge whether other work is reasonable or not.

So when people ask me, many times I say that I would be the last person to tell you that this is not feasible. Because so many times I heard that. I don't have enough information. But the people would not acknowledge that. They would make judgements and say, “No, it's not good”.

People think that if they gave everybody some money to develop their idea, then if from a thousand people one would come up with something, that would already be worth it. We know that failure is always there. This is why we call it… I am not a “searcher”, I am a researcher, research, because re re re: redoing, retesting.

WALKER: I like that.

KARIKÓ: And then for me, although it is a basic science, but from day one, when I started to work, even in the fishery institute to understand how the food we give to the fish would influence the fat, and then working with Yanu in developing antiviral compounds, there was always the usefulness. “It will be good for something.” And that was the same when I was here at Penn when we could deliver to the cell the RNA and we could express the protein. “Oh, it will be good for some cell therapy” and thinking: “Oh, maybe for bone transplantation. Maybe even older people can give bone marrow because now we can extend the tip of the chromosome.”

And so always it was in my mind: “Oh, usefulness”. And now that people are doing it with mRNA, I am so happy because actually I also tested that, and there are many ideas which I have.

Now that many people are trying, more money is coming to the RNA field, I am sure that many new products will be developed. Because even if the final product would be protein but accelerates the search, the research, the development of a product, because with RNA it is so easy. We are here, I have a template… Actually without PCR also you can have in vitro transcription, so you can have a gene and plasmid and then you can make RNA. I mean, it takes 30 minutes. You already have the RNA. I put it on the cell, ten minutes later I can see the protein. That's unbelievably powerful to think how quickly you can do anything and then you see the outcome. I am very optimistic about the future because it will accelerate the science, the discoveries and the medicine should be cheap also, because the RNA is cheap to make.

WALKER: Yeah, it's magic, many good things about it.

WALKER: Okay, so. Putting aside simply giving everything more money, how should we reform how the biosciences are funded? So if you could wave a magic wand and change how the biosciences were funded, what would you do? But it can't just be giving more money.

KARIKÓ: I don't know what should be done. I don't know.

WALKER: But do you have any opinions based on your experience?

KARIKÓ: So many things are changing how it happened before. I was just reading yesterday that no longer can we review every paper which gets published. There are not enough people who could do that, critically reading something that was a peer reviewed paper. No, there are not enough scientists, the scientists have to do the research. They don't have time to read zillions of papers. Everything is difficult. So there are venture capitalists who are risking their money in believing that some ideas are good. But I don't know. Many things right now are going to be produced. I would bet that it won't work. But I wouldn't say. I don't know. Even if you would say more money will be there, what should be done. Yeah, I don't know.

WALKER: There's an interesting question about ego. So ego has kind of been a theme of this conversation. I get the sense that you're not someone who's driven by ego or seeking recognition, but obviously many scientists are, and I wonder whether we view that as a problem or potentially like an opportunity that we should harness. Do you think we should be celebrating scientists more?

KARIKÓ: I have to say that at the Gardener award ceremonies part of it was that I had to talk to high school students. There were 300 of them and each of them could name a hockey player. But when I asked if they could name just one living Canadian scientist, there was no name, they couldn't. So one question is why we don't know about all of these discoveries? All of the scientists discovering things.

In the morning, people are taking their pills, saving their lives. They never ask: “Who came up with this? Who's saving my life? Who is this person? I want to know.”

James Allison and Honjo, they did these checkpoint inhibitors. They got the Nobel prize for it. But do you think that the people who are getting lung cancer and other cancer and surviving because they get these checkpoint inhibitors, that they know: “These are the guys, they saved my life!” No.

And when I ask reporters: “Why are you not writing about them? Why about the celebrities, why is it more important who is breaking up or marrying or whatnot?” They say this is what the people want to hear. But I said: “They read about it because that's what you are writing. Write about the science. The science could be so important. Looking at the Super Bowl and running with the ball… Running at the gel and getting the example or some result is just as exciting.” And why don't we know about all of these discoveries, what is happening in these days?

My daughter got this non-invasive pregnancy test when they can identify from her blood whether her child has down syndrome. And I met the guy, Dennis Lo, we got the Lasker award together. He discovered… This is such an important thing. Do you think that the people who are getting this test non-invasively, that they appreciate, do they know about him?

Where should we start this? In April I will get the Breakthrough Prize, which is supposed to be the Oscar of science — red carpet event. But yes, I think scientists should be recognised. The achievement and the people's interest. Writing about it — or we are talking about it today, so you are doing your part — so that they would know what they discovered.

WALKER: Yeah. And that will then incentivise more brilliant people to become scientists.

KARIKÓ: Exactly.

WALKER: Yeah. I guess that kind of implies that ego is a useful thing because we're kind of playing to their egos.

KARIKÓ: Yes, of course you have to have the desire. But when the goal is to be recognised… I think that the goal should be that you should discover and understand and then present and then get some solution, for diseases or something. So many diseases we don't even know what is the reason and the cause for those symptoms. And without this, we don't know how to treat them. So we need more scientists and more women. Because the women think differently, they multitask. We need all of the young minds to come, and I can see that less and less people want to come to science. They want to be, I don't know, an influencer or something.

Ego is the number one thing which… I, personally, never had that desire to be recognised. Again, I can imagine how people doing all of this work and then they are not recognised can go crazy. But this Selye thing… Who cares? 100 years, nobody knows I ever existed. I am doing this, I can do that. And I do not crave that. But there are people who are not like that, and they are miserable. So anyway.

And for me also, I was so on the other side, you know, being very humble, the background, you know, nobody… I mean, coming to America, you could imagine, I had no classmate. I had not a single person I ever seen in my life who would be here. And there is no credit card.

That's what makes the immigrant great. Because then no matter what, I have to survive. I have my family here with me, I get them here and then what will we do? And then you will be fearless because the whole thing is gambling, coming here with that kind of… even one thousand dollars is not much, you understand? So it completely changes you.

People ask “Why couldn't you do this in Hungary?” Can you imagine? I was working nine months in Bethesda and I had no street address. I slept in the office, under the desk. We couldn't afford to live in two different places. We didn't live in this house, we just rented. But my daughter went to school here and I am 200 miles away. Coming and going weekly. Do you think in Hungary I would do that? No. I would ask somebody, my classmate, somebody to help me out. But nobody was here.

WALKER: Yeah, it's a difficult thing being an immigrant. But so many people have become so successful because you don't have a choice.

KARIKÓ: Because hardship is forming your character much better than when somebody is arranging for you to walk. Because you don't learn how. And you appreciate everything you have more than if it is given to you. “They accepted me. Okay, I got this.”

WALKER: Yeah, absolutely. My last meta-scientific question. As we've discussed, you and Drew Weissman met at a photocopier which is pretty close to the classic water cooler conversation, just with a different machine. Has the COVID induced shift to working from home reduced the number of those serendipitous conversations? Is there a chance that you and Drew may never have collaborated if you'd both been working from home? And what has been the net impact of working from home on scientific research? Do you think overall it's a positive or a negative?

KARIKÓ: It is definitely important that scientists should talk to each other. You know, that's why you go to meetings and so on. And some pharmaceutical companies don't let you take out the coffee from the cafeteria. You have to drink there, and while you are drinking, you are talking to colleagues. And you cannot go back to your office and just drink that coffee next to your computer. You have to talk to somebody. So that's important. Of course, it’s important. I told you all of what we try to do with Eliot Barnathan and with David Langer: he was telling me about the patient and what is causing [the patient’s problem]. And then I was telling him about what I can do with RNA, and how it would influence, what RNA would be the best. And so that conversation is leading to new discoveries and new treatment. Yes, of course it is important.

It is good, from time to time, to concentrate and stay home and think, and read, and do other things, definitely. I also mentioned that I worked at the bench, and I found that working at the bench is also helpful. I was 58 working, still pulling the gel and… So many things came to my mind when I was in the middle of the experiment, thinking about what this molecule is doing, and what could be the outcome, and maybe what other outcomes will be, and how to explain it. I enjoyed it, and then of course many technical things I improved. So I found it beneficial for me to work with my hands for that long.

WALKER: Some questions about the future, just to finish. Do you predict that pretty much all vaccines will move over to mRNA technology?

KARIKÓ: You have to understand that the RNA codes for a protein. And many bacterial vaccines… the bacterial surface is sugar, complex sugar. So that might be a different situation. But intracellular bacteria, like tuberculosis and others, it will be similar, like in a cancer vaccine — because you have to generate cellular immunity. A T cell had to recognise the infected cell. Just like the T cell had to recognise the mutated cancer cell.

At Penn, when they introduce me, they usually said: “Did you know Katy’s daughter is an Olympic champion?” The people didn't say: “Did you know Katy works with mRNA?” Nobody said that. I was the famous mom. I was the mother of Susan Francia. And then, we went to the Olympic games and everywhere I was introduced as, “She's Susan’s mom”. Now that I am getting the awards, and my daughter is coming with me, and now she's recognised: “She's Katy's daughter”.

WALKER: That's funny.

KARIKÓ: Now it is changed. And now she works for a company, actually, trialling, which produces the cap part of the mRNA. And now she's bragging, always, that her mother is me. So things change.

WALKER: They do, yeah. That's so funny. Currently Moderna, BioNTech, are working on mRNA based vaccines for a range of different things including HIV, Zika, a few kinds of cancer, there's the flu one, malaria, genital herpes, tuberculosis, food allergies, sickle cell anaemia, other autoimmune diseases. I'm interested in the cancer vaccines in particular. How does that work and what's the timeline on those? When do you think we could expect those?

KARIKÓ: I am not expert on this one.

WALKER: Okay, yeah.

KARIKÓ: You have to understand that to make a vaccine against a pathogen like a virus, you need antibodies. The antibodies recognise the protein on a particular surface. Now when this pathogen enters inside the cell, the antibodies cannot see it. You need cellular immunity. The cellular immunity, those T cells, one of them, which can make cytokines and which recognise some kind of thing presented by these infected cells, showing a little part of the virus. And then that T cells secrete things: “Come here, come here. Problems” and then there are killer cells coming in and they kill. So there are two types of T cells that eliminate.

When you have a cancer, most of the time you don't have any protein put on the surface. You don't need antibodies. In some cases you have a specific protein, but most of the time the cell just maybe has an extra chromosome, and then it just divides, divides and then it cannot fit in the bone marrow and they come out and those are immature cells and it’s a different kind of cancer. There is not even a mutation in it. So how would the immune cells recognise that it is something wrong? But when there is a mutation, then maybe they present something, and then these T cells recognise that it is not something they’re supposed to see.

You know how the immune system works, how from your thymus the cells are coming out which have different receptors. And then, here in your thymus — mine is gone, I am too old — but they have to go through on that like a mat. And then in your thymus, every protein in your body, even which is in your brain is expressed. And if your T cell is coming and sticks to it, they cannot come out, they die. And those who cannot stick to anything, they come out sitting in your lymph nodes and waiting for information. And these dendritic cells, they are going around eating things, always some debris, and then on their way stop by at the lymph nodes. T cells sitting there and then these dendritic cells haven't seen any danger, so it's presenting things on their surface, and then these T cells with the receptor show them that: “If you see this, you have tolerate it, because everything is normal.” They go out and then pick up something and big bang, the Stimulant is there and says: “This is danger.” Dendritic cells next time run to the lymph node. The T cells are sitting there and they say: “Guys, that's dangerous.” And then, what these T cells are recognising and trying whether their T cell receptor fits to this little epitope when this MHC is hold up. And when it fits, they get this thing: “Now you have to divide, divide, divide.” Then you start to see your lymph node is getting big. That's good news. You found your pathogen will be fought because T cells found it. And then these T cells divide, divide, and run out, and see this kind of thing that they can bind. And they find those infected cells and then they start to eliminate them. This all happens in the space of your body. That simple.

WALKER: Wow. At the moment, what's the biggest constraint on developing mRNA vaccines?

KARIKÓ: As you could see, they started to work on like… There is HIV. Moderna has a programme for that. But you have to know that HIV is a virus which is covered with sugar, so the antibody can see the protein, but it’s covered.

And one part is not. And that is the part, which is not important, constantly mutating and so tricking and exhausting the immune response. So the pathogen is very critical. SARS-CoV-2, this virus was a simple one. Easy. HIV, working more than 20 years to develop a vaccine is difficult, because the pathogen is very tricky.

You can see that they try to develop vaccines against viruses that we don't have any vaccines against. But now, you can see that both companies, Modena and BioNTech, announced with Pfizer that they will have a vaccine against Shingles. Right now Shingrix is a very good vaccine, but in Europe it is like €800 or €600. The vaccine is very expensive. So hopefully the RNA vaccine would be much cheaper.

So there are a lot of efforts to develop new vaccines or replace some of them, which are maybe good but very expensive, or maybe not that good. You will see this trend. And of course, beside these infectious disease vaccines, there are therapeutic applications and more and more companies are formed. The larger companies we talk about, Moderna, BioNTech, Pfizer. But you know that even Sanofi has Translate Bio, purchased that RNA company. And there is CureVac there, which was the first one, established in 2000, that also worked on a vaccine with GSK. And so, there will be more vaccines and more protein products based on mRNA.

WALKER: My final two questions. What was it like getting your first COVID vaccine knowing that that couldn't have happened without all of your efforts and all of your struggle over the years. Can you tell me that story about that moment?

KARIKÓ: Yeah, I have to say or correct you, because every time I think about all of the other scientists. I established my work on theirs. And also all of the scientists, and colleagues, and BioNTech, and Pfizer, and Moderna.

Together with Drew Weissman, we were getting the BioNTech-Pfizer vaccine. I was very excited. I can be a little bit emotional.

And then, when we were walking there, to this room, they already had cameras set up, that we will officially get this vaccine. In the other neighbouring room, they were already giving vaccines to the healthcare workers at Penn, who worked in the hospital. And then my new chairman said that we are the people who invented the vaccine or something like that.

And these people just started to clap, and I was just realising, I became so emotional, that was overwhelming for me. And getting the vaccine, seeing the needle there, and then the syringe, and seeing that the vaccine is there. And I worked in BioNTech and very much I knew what sequence and what structural elements were there because we worked on it, my colleagues. From day one I went there. Formulation, for example. The formulation, the lipid nanoparticle that my team, we screened different formulations and we zeroed in, with aquitos formulation, and did many improvements on the construct.

WALKER: I love that story. That makes me so happy. Last question, what are you working on at the moment, and what's exciting you?

KARIKÓ: I won't talk. I don't want hope high, because I could be wrong.

WALKER: I should let you go.


WALKER: Katy, thank you so much for everything you've done, and thank you so much for your time today. It's been an honour.

KARIKÓ: Thank you for asking. But again, I am saying that in the name of all of those people who came before us, who work with us, I am accepting that thanks in their name also. Because so many times I was reading articles, and I don't know those people but I felt that I would hug them.

WALKER: Yes, thank you to those people as well.


WALKER: Alright. Thanks, Katy.

KARIKÓ: Alright.