The Paper that Launched My Career

I can start with the paper that I think was the one that launched my career. I think there is always this “one” paper that is going to give you enough identity in the field, that allows you to develop an entire program around it, and that was the paper I wrote during my postdoctoral fellowship. This first paper came because I was, as I mentioned before, extremely interested by the idea of microbial persistence, by this enigma, how do you have a microbe that is able to stay for some time, the entire life of an individual – that's an enigma. Especially because we know that these microbes elicit immune responses, so something was actually blocking this immune response, something was keeping this immune response in check. I had actually discovered during my postdoctoral fellowship that a cytokine that's called IL-10 was important as a break to prevent the immune system to clear the pathogen.

Linking Regulatory T Cells and Infection

What this paper, and the paper I want to talk about actually said, was it came from a very interesting observation that we had a lot of lymphocytes that were accumulating at the site of chronic infection which is acidic for lymphocytes. I remember going to see a talk, it was actually from Jeff Bluestone, and it was at the time when regulatory T cells had been rediscovered and this was this important cell that was described as very important to prevent autoreactivity that was blocking the recognition of self. I remember watching this talk and it was at the seminar series that we had at the NIH that had nothing to do with my work, but there were these lymphocytes and these lymphocytes resembled the lymphocyte I had in my chronic infection. I think somehow this was when I started to make the link between regulatory T cells and infection, and at the time this was a very, very controversial point because everybody was telling me the regulatory T cells can only recognize self.

Using Leishmania major as a Model Organism

I used, in fact, my favorite microbe, which was the one I started to work [with] when I was an undergrad, which was Leishmania major, which is a parasite. I think parasites are the best teacher of the immune system because they are incredibly clever at manipulating the immune system. In fact, the same microbe that I used as an undergrad to try to understand diagnostics in the field against the microbe was the one [that] I used to do [the] sophisticated immunological experiment that really put regulatory T cells in the mix.

Regulatory T Cells Mediate Microbial Persistence

I started to look and I started to find that indeed the [regulatory T] cells were there and they were literally the cells that were blocking response against the microbe, and yes, they were recognizing microbial antigens. I remember the first few times I presented this work, how much resistance I had because the dogma was these cells were only able to recognize self, but I think that's the thing. When you believe strongly in your data and you're candid and you're honest with them, I think at one point you're convincing people and this is actually what happened. This paper is the first paper that is describing the role of regulatory T cells to mediate microbial persistence, and really the first paper that is putting regulatory T cells and infection together. It hadn't been done before.

The Basis of My First Lab

This [paper] was published in 2002, so this was really when I started my career. This paper, when I was corresponding author, was the paper that became the base of my first lab when I started my own, and this is the thing that is the most important. When you finish a postdoc, it's not about how good you are, it's how unique you are because that's what really is going to give you the possibility. This paper placed me in a very unique position. I was very lucky to be identified as a person that had discovered microbes and regulatory T cells. [It] gave me a window, it gave me a space, it gave me enough resources to actually build a career.

Yasmine Belkaid is a renowned scientist whose research focuses on the relationship between microbes and the immune system. She is the President as well as the head of the Metaorganism laboratory at the Institut Pasteur.

Belkaid earned her Master’s degree in biochemistry from the University of Science and Technology Houari Boumediene in Algiers, and a Master of Advanced Studies (DEA) from Paris-Sud University. In 1996, she earned her PhD in immunology from the Institut Pasteur, where she studied innate immune responses to leishmania infection. Belkaid then moved to the United States for a postdoctoral fellowship in intracellular parasite biology at NIAID’s Laboratory of Parasitic Diseases (NIH).

Belkaid has received numerous awards including the Robert Koch Prize, the Lurie Prize in Biomedical Sciences, the Sanofi-Institut Pasteur Prize, and the AAI Excellence in Mentoring Award. She also serves on the committees of the American Academy of Arts and Sciences, the National Academy of Medicine, the National Academy of Sciences, the Microbiome Technical Advisory Group at the Bill & Melinda Gates Foundation, the NIH Anti-Racism Steering Committee, the American Society of Microbiology, and the Genentech Scientific Resource Board.