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cytokines. By. Dr. Emad AbdElhameed Morad. Lecturer of Medical Microbiology and Immunology. Cytokines are low molecular weight soluble proteins that regulate the amplitude and duration of immune response.
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cytokines By Dr. Emad AbdElhameed Morad Lecturer of Medical Microbiology and Immunology
Cytokines are low molecular weight soluble proteins that regulate the amplitude and duration of immune response. • Cytokines secreted by lymphocytes are called lymphokines, those produced by macrophages are called monokines. Some of them have been termed interleukins, tumor necrosis factor and interferons. Dr. Emad AbdElhameed Morad
interleukins Dr. Emad AbdElhameed Morad
Tumor necrosis factor Dr. Emad AbdElhameed Morad
TNF α is secreted with IL1 and IL6 from macrophages in response to infection. • These three cytokines are called proinflammatory cytokines because: • They act on the hypothalamus producing fever. • They stimulate the liver to produce acute phase proteins. • TNF β (lymphotoxin) is produced from TH1 cells. Its actions are similar to TNF α. Dr. Emad AbdElhameed Morad
interferons Dr. Emad AbdElhameed Morad
Interferons have two types І, ІІ. (Type І interferon) • Type І interferon is: * IFN α which is produced from macrophages. *IFN β which is produced from fibroblasts. • Type І interferon is produced from virus infected cells. • It protects the nearby healthy cells from the virus by inhibiting translation of viral m RNA viral thus inhibiting its replication. Dr. Emad AbdElhameed Morad
(Type ІІ interferon) • It is also called IFN γ. • It is produced from TH1 cells • Actions: • It causes activation and recruitment of macrophages. • It increases expression of MHC class І, ІІ and costimulatory signals on macrophages. • It inhibits TH2 cells. • It stimulates B cells to secrete IgG2. Dr. Emad AbdElhameed Morad