Mammalian immune-system bone-marrow cells {B cell}| synthesize and secrete antibodies and migrate to spleen, liver, and lymph nodes. If antigens meet B cells with correct antibodies, B cells transform into plasma cells.
antibodies
B cells differentiate from making IgM to making IgG to making IgA. B cells transpose variable region, located far from constant-region gene, to joining region, to make different antibodies. Enhancer activates only one variable-gene promoter. Vertebrate immune-system B cells use controlled transposition to make one antibody. Antibodies have constant regions. Various joining regions can attach to constant region. Various variable regions, located far from constant region in genome, can transpose to joining region.
Cells {memory cell} can take information back to lymph nodes or spleen, where memory cells change to plasma cells.
Cells {plasma cell}| can come from B cells. Plasma cells are lymphocytes that make antibodies and bind to foreign proteins. They make only one antibody type, which reacts with antigen to form precipitates for phagocytization. Humoral system makes 2000 antibodies per second for several days to prevent re-infection. Immature plasma cells in fetus that make antibodies against self normally die, leaving only antibodies against foreign molecules at birth.
IgD are on B-cell surfaces. IgE starts cells {mast cell}| that make histamine.
Immune-system cells {natural killer cell} can attach to B cells at temporary synapses to check if they are functioning.
4-Zoology-Organ-Immune System-Cells
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Date Modified: 2022.0225