BIOL 1010U Lecture Notes - Autoantibody, Polylysine, Basophil
Document Summary
Molecular basis of humoral immunity: ab structure and fxn. Bacteria can evade innate immunity 1. shielding targets (encapsulation) Mediated by t and b lymphocytes-carry receptors for specific antigens. B cells differentiate into ab (ig-recognition element) secreting plasma cells. Soluble ig mediation of host defense (detect free antigen: neutralization of viruses and bacterial toxins. Ab prevents bacterial adherence or uncoating (neutralizes usual receptor mediated fxn of antigen: opsonization-facilitation of phagocytosis phags, complement activation. Ab can coat cell or make capsule more rigid to help the. Complement: augments phagocytosis, b cell responsiveness, and microbial killing by ab (a) enhances opsonization (b)lysis bacteria. Membrane bound ig: triggers lymphocyte activation (w/ 2nd signal from t cells, mediates antigen uptake for presentation to reactive t cells. Not secreted!!! (can detect antigen expressed inside cell ) 1 response = 2-4wks later specific antibodies appear. Time lag = clonal expansion and differentiation of b cells to plasma cells (ab secreting)
