PMI 126 - Lecture 15

PMI 126 - Lecture 15 - PMI 126 Lecture 15 IL-6, TNI-alpha,...

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PMI 126 – Lecture 15 IL-6, TNI-alpha, and IL-1: all three induce fever, induce change in vascular endothelial cells, induce the recruitment of neutrophil. IL-2: autocrine growth factor Cytokines : soluble messengers of the immune system - small molecular weight proteins and glycoproteins - have several names: o lymphokines – secreted by lymphocytes o monokines – secreted by monocyte and macrophages o interleukins – large number factors produced by large number of WBC and other cells in the body can also make it. o Chemokines – subpopulation of interleukins (substances that are produced AS soluble mediator that attracts WBCS, and drives cells move toward certain locations) How does it work? - induce stimulus o Get signal transduction into the nucleus Transcription of certain cytokine Cytokines are secreted o Bind to the receptor on another cell (only way to have an effect on another cell or the cell itself) Three categories: Autocrine action : cell produces the cytokine also express the cytokine receptor on the surface (ex. IL-2 – T cell growth factor) Paracrine action : cell produces the cytokines that bind to the receptor on the nearby cell. - has effect in a short range and on nearby cell - ex. SMCK between T-helper cell (IL-2,IL-4,IL-5) and B cell Endocrine action: cytokines act as the same way as hormone. - cytokine moves throughout the circulation and bind to the receptor on the distant cell - IL-6, IL-1, and TNI-alpha (induce fever and other reactions) Examples of how interleukine work: IL-4 has pleiotrophy effect (different effect on different cells) - B cells, Thymocyte, and Mast cells have receptor for IL-4 - B cells would have activation, proliferation, differentiation, and class switching . (would secrete IgE) - Mast cells under the endothelial surface that has high affinity of IgE receptor Redundancy effect : all three IL-2, IL-4, and IL-5 induce the proliferation of B cells.
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: Il-4 and IL- 5 work together to induce the class switch to IgE of B cell. Antagonism effect (interfere with the production of each other): ex. IL-4 and IFN-gamma IL-4 causes the class switch of B cells IFN-gamma interferes with the action of IL-4 on the B cells Most of the time, both occur at the same time to get a balance! Pleiotropic Effect of IFN gamma: produce IFN-gamma. - Down-regulate the proliferation and production of IL-4 and IL-5 by Th2 cell - Activation of macrophage (increase expression of both classes MHC) . Respiratory burst works better. - Dendritic cells increase expression of MHC II. - IFN-γ activate NK (in autocrine fashion) , which increase the cytotoxic activity - IFN-γ activate B cells (in autocrine fashion). (IgE is down-regulated is due to the blockage of Th2 cell by IFN-gamma) Pro-inflammatory Cytokines Destruction of Activated T H cells => try to deal with tissue transplant or autoimmune disease => need to interfere with the activation of T cells. => Put toxin on the IL-2
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PMI 126 - Lecture 15 - PMI 126 Lecture 15 IL-6, TNI-alpha,...

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