Figure 1.

Schematic representation of the different fates of GC B cells that lead to GC volume changes: GC B cells proliferate in the DZ and increase in number. SHM accompanying proliferation might induce deleterious mutations in the BCR gene of some of the B cells, thus activating apoptosis in these GC B cells. Lack of acquisition of antigen, survival signals from FDCs and signals from Tfh cells lead to the apoptosis of GC B cells in the LZ. On the other hand, successful acquisition of these signals could result in the differentiation of the GC B cells into effector cell types such as memory and plasma cells that exit the GC. Alternatively, selected cells can move back to the DZ by a process termed recycling and undergo further rounds of divisions thus contributing to an increase in number of GC B cells. Green and red arrows represent processes that increase or decrease the GC volume, respectively and influence GC shutdown. GC, Germinal Centres; BCR, B cell receptor; FDC, Follicular Dendritic Cells, Tfh, T follicular helper cells, B, GC B cells; Tfr, T follicular regulatory cells; PC, Plasma cell; B_m , Memory B cell; Ag, Antigen.