PSL301H1 Lecture Notes - Lecture 3: Histocompatibility, Mhc Class I, Adaptive Immune System
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PSL301H1 Full Course Notes
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Acquired immune responses are anigen-speciic responses in which the body recognizes a paricular foreign substance and selecively reacts to it. Acquired immunity is mediated primarily by lymphocytes, which secrete cytokines that act on immune cells, non-immune cells, and on pathogens. B-lymphocytes develop into plasma cells when acivated. T-lymphocytes develop into either cells that atack and destroy virus-infected cells (cytotoxic t cells), or cells that regulate other immune cells (helper t cells) when acivated. Nk cells destroy virus-infected cells and tumour cells, as part of the innate response. Speciicity - acivated by and responds to a speciic anigen! B-cells and t-cells have receptors that recognize speciic shapes. Versaility - ready to confront any anigen at any ime. Memory - remembers any anigen it has encountered, and can act faster aterwards. Some acivated b-cells and t-cells are long lasing! Tolerance - responds to foreign substances but ignores normal issues (problem if autoimmune)