醫(yī)學免疫學英文版教學課件：Chapter 7 Cytokines

1、 Chapter 7 Cytokines Definition and general properties of cytokines). Definition A group of low molecular weight proteins which are secreted by activated immunocytes and various other cells, which possess high activity and various functions.Eg. Lymphokines , Monokines, IFN, InterleukinMajor function

2、s : .Mediate and regulate immune response .Inflammatory reactions.). General properties of cytokines1.Low molecular weight polypeptides or glycoprotein(60KD), and they are monomer, dimer or trimer.2. Secreted by cells which were activated with antigen, mitogen or other stimulators. activated immune

3、cellsmatrix cells some tumor cells.3.One kind of Cks can be produced by different cells. One kind of cells can secrete different cytokines. IL-3,GM-CSF,TNF- IL-2 IFN-,TNF- IL-4，6 IL-5 TH1TH2 Distance autocrine endocrineBlood circulation paracrine Nearby self4. Cytokines act on target cells by the wa

4、y : paracrine autocrine endocrine 5.Cytokines initiate their actions by binding to specific membrane receptors on target cells. with high affinities. Three forms of the IL-2 Receptor(CD25)6. The effects of cytokines : pleiotropism, redundant, synergy, antagonism, and form a cytokine network.Pleiotro

5、pism the ability of one cytokine having multiple effects on diverse cell types.Redundancy the property of multiple cytokines having the same or overlapping functional effects.Synergy the property of two or more cytokines having greater than additive effects.Antagonism refers to the ability of one cy

6、tokine inhibiting the action of another. Classification of cytokines Interleukin, ILInterferon , IFNTumor necrosis factor, TNFColony stimulating factor, CSFChemokineGrowth factor). Interleukin (IL)Cytokines secreted by various cells that have the ability to act as signal molecules between different

7、population of leukocytes and immune cells.IL-1IL-38Th0ThpIL-12IL-4IL-2TNF-IFN-Th1Th2IL-10IL-4IL-5IL-13Ag). Interferon (IFN) A group of glycoproteins produced by human or animal cells following infection of virus or exposure to various inducing agents. Comparison of IFN-, IFN-, IFN-_ Types Produced c

8、ells Main functions_ IFN- leukocyte anti-virus, immune regulation IFN- fibroblast anti-tumor Virus infected cells IFN-Type II Th1,NK weaker anti-virus effect immune regulation effect anti-tumor_Type IAnti-virus effect of type I IFNImmune regulation effect of IFN- Immune regulation effect of IFN- )Tu

9、mor necrosis factor (TNF) TNFs were originally thought of as selective antitumour agents, but are now known to have a multiplicity of actions.TNF- is produced mainly by monocytes and macrophages.TNF-(lymphotoxin, LT) is produced by lymphoid cells. ). Colony-stimulating factors (CSF) Cytokines that s

10、timulate proliferation or differentiation of pluripotent hematopoietic stem cell and different progenitors. Multi-CSF (IL-3) Granulocyte/macrophage-CSF, GM-CSFGranulocyte-CSF, G-CSFMacrophage-CSF, M-CSFStem cell factor, SCFErythropoiein,EPO). Chemokine Chemokines are cytokines which recruiting monoc

11、ytes, granulocytes and lymphocytes in blood to sites of inflammation.CXC chemokines( subgroup):IL-8CC chemokines( subgroup):MCP-1C chemokines( subgroup)CX3C chemokines( subgroup)*C: cysteine; X: any amino acid Chemokine Effects Chemokine Function Chemokines promote chemotaxis in the direction of hig

12、hest concentration). Growth factor Growth-factor are cytokines which stimulate the growth of their target cells.Transforming growth factor-(TGF- )Epithelia growth factor(EGF)Vascular endothelia cell growth factor(VEGF)Fibroblastic growth factor(FGF) Cytokine receptors1. Membrane-binding cytokine rec

13、eptors The receptor consists of extra-cellular region, trans-membrane region and cytoplastic region.2.soluble cytokine receptorsSome cytokines use a common chain for signal transduction2.soluble cytokine receptors Biological functions of cytokines1.Take part in nonspecific immunity -anti-bacteria, anti-virus 2. Take part in specific immunity3. Stimulate hematopoiesis4. Take part in inflammatory reaction Cytokine and diseaseCy