Biology Seminar - Ali Ellebedy | Tuesday, May 9th, 2023 - 4 pm

Date: Tuesday, May 9, 2023

Location: Chen 100

Reception: 3:30 pm

Seminar: 4 pm

Speaker: Ali Ellebedy, Associate Professor

Washington University in St. Louis

Faculty Host: Pamela Bjorkman

Title: "Dynamics of Germinal Center B Cell Responses in Humans"

Abstract: Germinal centers (GCs) are microanatomical lymphoid structures where the maturation of antigen-stimulated B cells occurs. This process is critical for generating high-affinity and durable antibody responses to infection and vaccination. For decades, studying the dynamics of GC responses to vaccination has been confined to animal models because GC cells do not circulate in blood, making it challenging to study such responses in humans. Our lab has pioneered the use of a fine needle aspirate-based approach to serially sample draining lymph nodes after vaccination in humans. Using this approach, we answered a long-standing question in the field regarding the origin of the B cells comprising the GC reaction in response to influenza vaccination in humans. Studies in mouse models have suggested that memory B cells are inefficiently recruited to secondary GC reactions. We showed that memory B cells could dominate the GC reaction after vaccination. We also demonstrated that SARS-CoV-2 vaccination-induced GC reactions in humans could persist for six months, much longer than predicted by experiments in animal models. In my talk, I will discuss the implications of these findings on our understanding of the biology of memory B cell generation and maintenance in humans.