NPB 101 Lecture Notes - Lecture 22: Natural Killer Cell, Innate Immune System, Signal 1
14 Oct 2018
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Innate immune system cells: phagocytes: earliest responders. Class of cells which eat dangerous substances and destroy them: macrophages: first responders, can engulf ~100 bacteria at once, neutrophils arrive after macrophages, stored in bone marrow until they"re needed. Drawn to infected area by chemicals released by infected tissue or the infection itself. Can engulf ~20 bacteria at once: monocytes circulate in blood until they"re needed. These release histamines and other chemicals when the antibody binds to a pathogen: antigen presentation, mhc"s (major histocompatibility complex (display antigens for recognition, signal 1 and signal 2: signals needed for b and t cell action. Both must be present for activation to occur: signal 1: bcr and tcr recognize its appropriate antigen, t-cells: signal 1 received from professional apcs. Apcs engulf pathogens and display antigen on mhc ii"s: b-cells signal 1 received when an antibody binds to multiple bcr"s on the same, signal 2 danger signal, received when there"s an actual infection occurring.
