F: IMMUNE SYSTEM RECOGNITION
BIOCHEMISTRY - DR. JAKUBOWSKI
Last Updated: 03/14/13
Learning Goals/Objectives for Chapter 5E: After class and this reading, students will be able to
There are a large number of different cytokines that are released from immune cells. Some examples and their activities are shown in the diagram below and described in the text that follows. They are
Cytokines released from cells such as macrophages in the innate IS:
Tumor Necrosis Factor: TNF - from activated macrophages and dendritic cells. Main mediator of acute inflammation. Induces fever and sleep by acting on sites in the brain. Promote scar formation (excessive wound healing). Too much can cause shock. Acts on
endothelial cells that line all blood vessel walls
facilitates the movement of immune cells from the blood into tissues through the endothelial cells.
activates neutrophils activates macrophages which leads to IL1 secretion kills some tumor cells.
IL-1 - has similar properties as TNF IL-12 -
Activates NK and CTL.
Leads to release of INF-g from NK and T cells.
Interferon a, b, w : Are produced by virally-infected cells.
cause cells to degrade mRNA which kills virally-infected cells. The enzyme involved in RNA hydrolysis is inactive until the cell becomes infected with a virus. This protects uninfected cells.
Cytokines released after antigen activation of T cells in the adaptive immune system:
IL-2 - Produced by T helper cells (CD4)
leads to the proliferation of NK cells and T and B-lymphocytes that have been activated by antigen exposure.
Interferon-gamma (INF-g) - is also produced by activated T cells
increases the activity of other T cells (CTLs, NK cells. principle way to activate macrophages.
induces expression of MHC-I molecules, MHC-II molecules on antigen presenting cells to promote presentation
IFN-g stimulates the differentiation of T4-lymphocytes into activated T helper cells.
Chemokines are chemotactic cytokines, or protein that recruit other cells towards the site of release. Some examples are listed below:
MIP (Macrophage inflammatory factor, CCL3,4) recruit MI, NK cells, immature dendritic cells
IL-8 (recruit neutophils)
IP10 recruit T cells
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