<Tr> <Th> TH </Th> <Td> H2. 00.03. 0.01006 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> Plasma cells, also called plasma B cells, plasmocytes, plasmacytes, or effector B cells, are white blood cells that secrete large volumes of antibodies . They are transported by the blood plasma and the lymphatic system . Plasma cells originate in the bone marrow; B cells differentiate into plasma cells that produce antibody molecules closely modelled after the receptors of the precursor B cell . Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction . </P> <P> After leaving the bone marrow, the B cell acts as an antigen presenting cell (APC) and internalizes offending antigens, which are taken up by the B cell through receptor - mediated endocytosis and processed . Pieces of the antigen (which are now known as antigenic peptides) are loaded onto MHC II molecules, and presented on its extracellular surface to CD4+ T cells (sometimes called T helper cells). These T cells bind to the MHC II - antigen molecule and cause activation of the B cell . This is a type of safeguard to the system, almost like a two - factor authentication method . First, the B cells have to encounter a foreign antigen, and are then required to be activated by T helper cells before they differentiate to specific cells . </P>

Where do plasma cells come from and what is their function