PSL201Y1 Lecture Notes - Lecture 10: Thymus, Immunoglobulin Light Chain, Mast Cell
Document Summary
Psl201 week 10 part a reading notes- specific immunity (pgs. Second type of defense is specific immune responses (adaptive immunity) come into play after nonspecific responses have already begun and are much slower mediated by lymphocytes which are very selective. Humoral immunity: b cell mediated, b lymphocytes developed into plasma cells that secrete antibodies. Defend against extracellular molecules- bacteria, toxins, and viruses in body fluids. Cell-mediated immunity- t cell mediated, certain t lymphocytes develop into active cytotoxic t cells which bind to and kill abnormal cells by lysis. Call cell-mediated because cytotoxic t cells must come into direct contact with their targets to act on them. Defend against molecules that are inside the cells. Part of reaction to transplants and cancer cells. Characteristics of specific immunity: specificity- b and t cells bind and respond to foreign molecules known as antigens. Antigens: complex proteins and polysaccharides of foreign invader or tumor cell.
