Pathology 3240A Lecture 11: Autoimmune Diseases
15 Oct 2018
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Document Summary
Immune system: the body"s defense mechanism against microorganisms and their products (toxins) Innate immune system: born with, not specific, does not require previous exposure to an antigen: epithelial barriers (skin, mucosal surfaces, phagocytes (neutrophils, macrophages) Attracted to site of infection via action of chemokines. Recognize microbes (via tlrs) and inflammatory mediators (via gpcrs, cytokine receptors, phagocytic receptors) Phagocytose microorganisms once they bind to the phagocytic receptor. Formation of phagosome (endosome that contains the microorganism) Formation of phagolysosome (fusion of phagosome with lysosome) Secrete cytokines to recruit other inflammatory cells: nk cells. Recognize and destroy virus-infected cells as well as other damaged cells and tumour cells. Recognize self via mhc i molecules (mhc i binds to inhibitory receptors on. Nk cells; damaged cells/tumour cells do not express mhc i and are thus destroyed by nk cells) Damaged or stressed cells may also exhibit activating ligands that bind to activating receptors on nk cells.
