PSL201Y1 Chapter Notes -Immunoglobulin G, Clonal Selection, Memory T Cell
Document Summary
B lymphocytes develop into plasma cells that secrete antibodies, the actions of which bring about humoral immunity, so called because antibodies circulate in the blood and lymph, body fluids long ago called humors. T lymphocytes develop into active cytotoxic t cells, which bind to and kill abnormal body cells (cell-mediated immunity); cytotoxic t cells must come into direct contact with their targets to act on them. The circulating antibodies of the humoral responses defend against bacteria, toxins, and viruses. T cells of the cell-mediated response are against bacteria and viruses that are hidden within infected body cells. It is much faster (2-7 days) greater in magnitude, and more prolonged than a primary response: secondary immune response give rises to effector cells and clones of long-lived memory t cells and memory b cells. Self-tolerance: b cells and t cells mature in the bone marrow and thymus.
