Figure 2.

(A) Schematic representation of B cells, antigen receptors, and antibodies. (B) Schematic representation of B cell development and maturation. B cells originally develop in the bone marrow, where through gene recombination, they develop a specific antigen receptor on its membrane (B cell receptor, BCR). Subsequently, B cells migrate to a secondary lymphoid organ where they can become activated upon binding their cognate antigen, secreting IgM. B cells can internalize and process the antigen, presenting it in the context of Class II MHC to CD4 T-cells. Upon recognition of their cognate antigen, it can stimulate B cells (T-dependent B cell activation), inducing the class–switch recombination process, first leading to the switch of the antibody isotype from IgM or IgD to IgE, IgA, or IgG. Further stimulation of B cells from the cognate antigen induces the somatic hypermutation process, leading to the development of antibodies with higher affinity to the specific antigen. Created with BioRender.com.