Presentation on theme: "Cytokines receptors and biological functions. Cytokine Receptors These are the receptors present on membrane of responsive target cells by which cytokines."— Presentation transcript:
Cytokine Receptors These are the receptors present on membrane of responsive target cells by which cytokines binds to exert their biological effects. Cytokine Receptors Fall Within Five Families Immunoglobulin superfamily receptor. Class I cytokine receptor family (also known as the hematopoietin receptor family) Class II cytokine receptor family (also known as the interferon receptor family) TNF receptor family Chemokine receptor family
Immunoglobulin superfamily receptor - It involves the receptor for IL-1, IL-6 and M-CSF. Also involves the receptor for MHC, TCR and Immunoglobulins. Class I cytokine receptor family - Also known as the hematopoietin receptor family. It involves the receptor for G-CSF,IL-2, IL-3, IL-4, IL-5 and IL-7. Structure - They have conserved amino acid sequence motifs in extracellular domain consisting of four positionally conserved cysteine residues (CCCC) and a conserved sequence of tryptophan-serine-(any amino acid)-tryptophan-serine (WSXWS, where X is the nonconserved amino acid).
Class II cytokine receptor family -The class II cytokine receptors possess the conserved CCCC motifs, but lack the WSXWS motif present in class I cytokine receptors. TNF receptor family - They involves the receptor for Tumor necrosis Factors (TNF- & TNF- ). They posses extracellular domain and intracellular domain. Extracellular domain consists of 4 cysteine rich domains.
Biological Functions of Cytokines Variety of cells can secrete cytokines, the two principal producers are the T cell and the macrophage. Cytokines released from these two cell types activate an entire network of interacting cells. Cytokines are involved in : - - - Development of cellular and humoral responses. - Induction of the inflammatory responses. - Regulation of hematopoiesis. - Control of cellular proliferation and differentiation. - Healing of wounds.
Immune response to a specific antigen may also include the production of cytokines. Cytokines act in a antigen-nonspecific manner. Cytokines effect any cells which bear the appropriate receptors and are in a physiological state to respond to cytokines. Cytokines are also involved in biological activities:- -innate immunity -adaptive immunity -inflammation -hematopoiesis.
Therapeutic Uses Of Cytokines Interferon in treatment of viral diseases, cancer. Several cytokines are used to enhance T-cell activation in immunodeficiency diseases, e.g. IL-2, IFN- ,TNF- . IL-2 and Lymphokine activating killer cells (LAK) in treatment of cancer. GM-CSF induces increase in white cell count, it is used: To restore leukocytic count after cytotoxic chemotherapy induced neutropenia. After bone marrow transplantation. To correct AIDS-associated leukopenia.
Anti-cytokines antibodies in management of autoimmune diseases and transplant rejection: Anti-TNF in treatment rheumatoid arthritis. Anti-IL2R to reduce graft rejection. Anti-TNF antibodies in treating septic shock. Anti-IL-2R in treating adult T-cell leukemia. Anti-IL-4 is under trial for treatment of allergies.
Cytokines in Hematopoiesis Hematopoiesis – (Heame - blood and poiesis - means to make). All blood cellular components are derived from Heame stem cells. So it is process of formation of different blood cellular components from Hematopoietic Stem Cells which is regulated by the different cytokines.