BIOC39H3 Lecture Notes - Lecture 11: Immunoglobulin Class Switching, Extracellular Fluid, Endothelium
8 Apr 2015
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Document Summary
Cytokines released by t cells influence b cell isotype switching. Il4: igg1, ige: tfn- : tgg2a, igg3, tgf- : igg2b, iga. Secreted as a pentamer by plasma cells in the bone marrow, the spleen and the medullary cords of lymph nodes. The pentameric nature of the igm enables it to bind to microorganisms strongly and quickly activate the complement cascade by the classical pathway. Complement activation coats the pathogen with c3b, enhances phagocytosis. Its large size decreases the extent to which it can passively leave the blood and penetrate infected tissues. Immune response proceeds, soma1c hypermuta1on isotype switching a nity matura1on. Have 2 high-affinity binding sites that are as effective as the 10 antigen binding sites of igm. Advantage: smaller, better able to get into infected tissue. Igg is actively transported from the blood into the extracellular spaces between tissues. Igg from fcrn, releasing igg into the extracellular space.
