Protective and pathogenic memory plasma cells.

The immune system can be divided into two major parts: innate and adaptive immunity. Adaptive immunity is characterized by its major cellular players: the B and T cells. B cells will, in the context of an immune reaction, differentiate into plasma cells. These plasma cells produce antibodies, which are secreted. Antibodies are characterized by their specificity against a selected antigen and by their isotype. The isotype changes with the duration or phase of the immune reaction. Early immune reactions are usually characterized by the predominant production of IgM antibodies. With the persistence of the immune reaction immunoglobulin class switch occurs and plasma cells will produce IgG, IgE or IgA-antibodies (Radbruch et al., 2006) [1].