Simplified version of negative selection processes that occur during B cell development. B cell development occurs in several stages. Rearrangement of the IgM B cell receptor occurs in the bone marrow before immature B cells are released into the periphery. To enable continued survival immature B cells enter the lymph node and need to take up antigen. Once they have taken up antigen, they interact with T cells (although interaction occurs through HLA class II molecules presenting antigen on the B cell surface and the T cell receptor for simplicity this is not shown) enabling them to start proliferating and form germinal centres. These proliferating B cells undergo IgG rearrangements before differentiating into mature plasma cell or memory B cells that express both IgM and IgG and can enter the periphery. Negative selection processes occur at several points to check that the randomly rearranged IgM and IgG are fully functional and are not autoreactive. In the light zone immature B cells with non-functional IgG rearrangements are apoptosed and those with autoreactive IgG receptors are either apoptosed or sent back to the dark zone for further rearrangements. Th, T helper; Ig, Immunoglobulin; Pro-B, Progenitor B; Pre-B, Precursor B.