Abstract

This Cambridge Immunology and Medicine Seminar will take place on Thursday 21 November 2024, starting at 4:00pm, in the Ground Floor Lecture Theatre, Jeffrey Cheah Biomedical Centre (JCBC)

Speaker: Prof Kai-Michael Toellner, Babraham Institute, Cambridge

Title: “Memory output from the Germinal Centre. A second level of selection?”

Abstract: Germinal centres are areas in lymphoid tissues where B cells affinity mature the genes coding for B cell receptors and antibody. This happens through a process of several iterations of B cell immunoglobulin gene hypermutation and selection that basically represents Darwinian evolution on a cellular level and, over several weeks, leads to a slow increase of antibody affinity. Higher affinity variants of B cells are selected for continued affinity maturation or to differentiate into antibody producing plasma cells. Germinal centres also produce memory B cells, and these are less stringently selected for affinity to antigen.

We followed the migration of memory B cells leaving germinal centre in lymph nodes and found that they interact with macrophages in the subcapsular sinus (SCS) of lymph nodes. The SCS is also the site of antigen entry into lymph nodes. I will show data that indicate that here memory B cells may undergo a further selection step. This can lead to recycling of memory B cells back into the germinal centre. The process may be important to sense variants of antigens arriving in the lymph node and trigger affinity maturation to antigenic variation.

Host: Georg Petkau, Babraham Institute, Cambridge

Refreshments will be available following the Seminar.