First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Sarantis Korniotis is first author on ‘ GM-CSF-activated human dendritic cells promote type 1 T follicular helper cell polarization in a CD40-dependent manner’, published in JCS. Sarantis conducted the research described in this article while a postdoctoral researcher in Professor Vassili Soumelis's lab at Saint-Louis Hospital, Université de Paris, France. He is now a Senior Scientific Associate in Immunology at Intelligencia AI, Athens, Greece, investigating new signals and factors that make cells acquire regulatory or immune-suppressive properties.

Sarantis Korniotis

How would you explain the main findings of your paper in lay terms?

Today, lots of people have become familiar with the scientific field of immunology – simply because for the past 2 years we were all worried about the efficacy and strength of our immune system to fight COVID-19. There are a group of cells that display ‘magic capacities’ by recognizing pathogens and activating an alarm system within the body, leading to the killing of the enemy. These cells are called T cells, and we want them in good shape to fight pathogens. T cells do not consist of one homogenous population; instead, there are several distinct subsets of T cells. Recently, the existence of a new population of T cells has been described: T follicular helper cells (Tfh cells), which have unique properties of providing signals to B cells to make them differentiate into antibody-producing plasma cells. The produced antibodies are much wanted in the fight against infections. However, the Tfh cells are not a homogenous population. In fact, there are three different subsets, which are involved in different disease settings. Among them, type 1 Tfh (Tfh1) cells have been shown to be present in viral and bacterial infections. How could we use these cells to enhance our immune responses? To answer this question, we needed to acquire more knowledge on the mechanisms leading to the generation of Tfh1 cells in humans. We are quite confident that our article in Journal of Cell Science gives answers to this important biological question.

Were there any specific challenges associated with this project? If so, how did you overcome them?

In this project, we worked exclusively with human cells derived from the blood of healthy donors. This means that our research is completely dependent on volunteers who provide blood samples for clinical and research purposes. Their contribution is highly appreciated, and this is an occasion for me to express my gratitude to these people. Unfortunately, during the first COVID-19 pandemic period, the donation centers were closed and we could not have access to fresh samples, but an option for us was to find frozen samples. More scientifically and technically speaking, some challenges I met included our decision to work with rare populations of dendritic cells (DCs) that required fluorescence-activated cell sorting for every single experiment. The help of research technicians in our cell sorting facilities was enormous. Finally, in our article, we include data from many different immunology-related experimental methods, such as flow cytometry, RNA sequencing, single-cell RNA sequencing, imaging and ELISA, which required efficient collaboration between several people with different scientific backgrounds. But this is the interesting part of academic research, isn't it?

When doing the research, did you have a particular result or ‘eureka’ moment that has stuck with you?

I would say when my partner-in-crime and second author of this article, Melissa Saichi, identified a clear population of Tfh1 cells in our single-cell RNA sequencing data and found significant correlation with specific types of DCs in tuberculosis and COVID-19 infection models. We both said “yes!” and became confident that our results do have physiological relevance.

Why did you choose Journal of Cell Science for your paper?

I love biology and like the way that biologists approach both basic and clinical research, and I think we needed the more objective eye of biologists in the process of scientific publication. I support not-for-profit charitable organizations that ‘use’ the science for the benefit of science.

GM-CSF induces the emergence of two morphologically different populations of conventional DCs. We observed that when GM-CSF is added to a homogenous population of primary blood conventional DCs, it induces diversification. ICOS-LHigh DCs display features of mature DCs, developing dendrites, whereas ICOS-LLow DCs seem to be less activated with no dendrites and high circularity.

GM-CSF induces the emergence of two morphologically different populations of conventional DCs. We observed that when GM-CSF is added to a homogenous population of primary blood conventional DCs, it induces diversification. ICOS-LHigh DCs display features of mature DCs, developing dendrites, whereas ICOS-LLow DCs seem to be less activated with no dendrites and high circularity.

Have you had any significant mentors who have helped you beyond supervision in the lab? How was their guidance special?

I consider myself very lucky regarding the scientific mentors I have met during my research career. The supervisor of this study, Professor Vassili Soumelis, is a great scientist, wonderful human and the coolest boss I could ever have. He is open-minded and gives space to young researchers to develop their own ideas. I am really grateful that he gave me the opportunity to be part of his team. I would like also to express my gratitude to two more people: Professor Terry Strom, who was my scientific supervisor at Harvard Medical School, and Dr Flora Zavala, who was the supervisor of my PhD at the Necker Hospital in Paris. Flora is the reason I fell in love with science and immunology and became what I am today. She offered me the best scientific training I could ever have, and she stayed close to me not only scientifically but also personally, providing endless discussions, advice and laughs. She believed in me and taught me how to be a good researcher. Thank you, all!

What motivated you to pursue a career in science, and what have been the most interesting moments on the path that led you to where you are now?

My need to explore. The unbelievable satisfaction I get when I am trying to prove a theory. Science is the most interesting game! You enjoy every part of it. From thinking to find out new ideas to the moment you get your final results that confirm (or not) your hypothesis. In science we do not simply work; we play using our mind and our body. I think it is the only job where you never get bored!

Who are your role models in science? Why?

My role models in science are my previous scientific mentors, including Vassili and Flora. Extremely smart and successful scientists who are cool and give space to young people. They are not micromanaging and let people grow through their supervision and guidance. They are only interested in doing correct and useful research, instead of being worried about the impact factor of the journal where they publish. Science is a continuous process of learning, listening and exploring, not a way to prove who is smart and who has the power.

What's next for you?

I have already left academia. Even though I spent many years as a postdoctoral researcher with a quite nice publication record, I decided to follow a different path. Why? Uncertainty, the very few opportunities for young people to become independent, the need to continuously fight to get grants, and our future being completely dependent on the impact factor of the journals where we publish papers. So, our future is dependent on the way of thinking of the few people directing the very big and famous scientific journals.

Tell us something interesting about yourself that wouldn't be on your CV

I am in love with my home, Lemnos Island in Greece. It is my personal paradise. I would be the happiest person if I could have an immunology lab there, doing my experiments and having a view of the Aegean Sea. Looking forward to meeting you all there!

Sarantis Korniotis’s contact details: Intelligencia AI, Athens, Greece. E-mail: skorniot@gmail.com

Korniotis
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S.
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Saichi
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M.
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Trichot
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C.
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Hoffmann
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C.
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Amblard
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E.
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Viguier
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A.
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Grondin
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S.
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Noel
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F.
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Mattoo
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H.
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Soumelis
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V.
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2022
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GM-CSF-activated human dendritic cells promote type 1 T follicular helper cell polarization in a CD40-dependent manner
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J. Cell Sci.
135
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jcs260298
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