Education

After vaccination, responding B cells may differentiate along the extrafollicular path, which leads to the production of short-lived plasmablasts, or along the germinal center (GC) route, which leads to the generation of long-lived plasma cells and memory B cells.

GCs are the primary site of affinity maturation, the process whereby the binding affinity of induced antibodies to vaccine antigens increases with time after vaccination. We have recently shown that mRNA vaccination against SARS-CoV-2 in humans can elicit a GC reaction that engages pre-existing memory B cell clones and de novo ones that can target new epitopes, broadening the spectrum of vaccine-induced protective antibodies.

These findings raised the following important questions:

1. What are the dynamics of vaccine-induced GC B cell responses in humans?
2. Do responding GC B cells accumulate somatic hypermutations (SHM) after mRNA vaccination?
3. Can a GC reaction be remounted upon repeat mRNA vaccination? These are some of the questions I will discuss in my presentation.