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S1P Gradients and T Cell Migration

27:10 recording · AUTO · 2 speakers

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Brief overview

Susan Schwab studies how the lipid S1P tells immune cells when to leave tissues.

  1. A food colouring exposed the tissue exit routeRats fed caramel color lost T cells from the blood, and chasing that oddity led to the vitamin B6-dependent enzyme that degrades the chemoattractant pulling cells into circulation.
  2. S1P is the cell's signal that a vessel is nearS1P is high in blood and lymph, so a T cell that sees it through S1P receptor 1 knows it has reached the place to leave — the basis of five FDA-approved drugs for multiple sclerosis and colitis.
  3. The first lab hires set the cultureSchwab credits Alejandro Mendoza and Willie Ramos, her first two graduate students, with setting a kind, collaborative tone that recruited everyone who followed.
Executive Summary AI
  • Cindy Leifer records this Immune booster at the American Association of Immunologists conference in Honolulu on May 5th, 2025, with Susan Schwab, a professor in the Department of Cell Biology at the New York University Grossman School of Medicine.0:46
  • Schwab started in social science and environmental advocacy at the Environmental Defense Fund and the Natural Resources Defense Council, then switched after a paper on air pollution and childhood asthma sent her into Nilav Shastri's undergraduate immunology course at Berkeley, where she ended up doing a PhD on antigen processing and the source of peptides for MHC class 1.2:27
  • In Jason's lab her secondary project became the real one: rats fed caramel color developed lymphopenia, and another scientist showed the difference between labs that saw the effect and labs that did not was the amount of vitamin B6 in the diet, because a vitamin B6-dependent enzyme degrades the chemoattractant that pulls cells out of tissues.6:38
  • Her lab now works on sphingosine 1-phosphate, which is high in blood and lymph and tells immune cells through S1P receptors that they have reached a vessel and can leave the tissue; caramel color inhibits the enzyme that degrades S1P, so levels rise in tissue and cells can no longer find the vessels.9:46
  • Five FDA-approved drugs now act on S1P receptor 1 in multiple sclerosis and colitis by trapping activated T cells in lymphoid organs, and the lab's newer tangent asks why acute lymphoblastic leukemia, the most common childhood cancer, reaches the meninges — probably through channels from the skull bone marrow rather than by an S1P-driven route.15:07
Key Quote
“I don't think you can ever, ever underestimate the importance of teachers.”
— Susan Schwab2:27
Key Quote
“It didn't have anything to do with regulatory T-cells, but his science was so beautiful.”
— Susan Schwab5:53
Key Quote
“But anyway, it turned out that the caramel color was absolutely fascinating.”
— Susan Schwab8:06