Memory B cells in allergy: ontogeny, phenotype and plasticity

Published on May 30, 2024   23 min

Other Talks in the Series: The Immune System - Key Concepts and Questions

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0:00
Hello, my name is Kelly. I'm a Postdoctoral Fellow at Stanford University. My research is centered around studying adaptive immune responses involved in IgE-mediated allergy. In the second part of this talk, I'll be discussing the role of B cells in allergy. And particularly, the ontogeny, phenotype, and plasticity of memory B cells implicated in allergic disease.
0:26
B cells play a central role in allergic disease. Type I hypersensitivities, which are reactions to something like peanuts or pollen are mediated by IgE, which is a particular antibody isotype. IgE will bind to high-affinity receptors located on mast cells and basophils. They coat the surface of these cells so that when the individual encounters the antigen once again, it will cross-link the IgE molecules, resulting in a rapid cellular degranulation and release of vasoactive mediators that ultimately cause the clinical symptoms of an allergy.
1:07
In the last decade, a central focus has been on understanding the features of immune memory that are directed towards allergens. Here we're discussing B cells. Allergen-specific memory B cells are actually dominated by IgG-expressing cells rather than IgE. This is in contrast to the memory to something like a virus for example, where the isotype of those memory B cells are usually of the same isotype that the primary factor antibody produced will be. Because allergen-specific memory B cells are held in this IgG state, it means that upon re-exposure to the allergen, it necessitates a class switch event so that they become IgE expressing, and then we'll terminally differentiate into plasma cells. This transient IgE state will be IgE-expressing B cells. It's actually short-lived IgE plasma cells that are produced rather than long-lived. The long-term capacity for plasma cells to persist appears to be lesser when the isotype that they're secreting is IgE-expressing. That means in the context of allergy, within the memory B cell compartment, is really where the memory is held. And it's those cells that must be reactivated in order to reinitiate or replenish that transient pool of circulating IgE.
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Memory B cells in allergy: ontogeny, phenotype and plasticity

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