5. Cytokine 细胞因子 王家鑫，孟明 Department of Veterinary Immunology College of Animal Science and Technology Agricultural University of Hebei

1. General Properties of Cytokines 1.1 Cytokines are polypeptides produced by immune cells (macrophages, mast cells, dendritic cells, and T cells ) and non-immune cells (epithelial cells, 上皮细胞 ) in response to microbes and other antigens that mediate and regulate immune response and inflammation reactions.

Cytokines are a group of intercellular signaling peptides and glycoproteins. Cytokines not only regulate immune and inflammatory responses, but also affect wound healing （创伤愈合）, hematopoiesis, angiogenesis （血管生成）, and many other biologic processes.

1.2.1 Interleukine(IL) ，白介素. IL-1, IL-2,IL Tumor necrosis factor(TNF), 肿瘤坏死因子 TNF-α ， TNF-β Interferon(IFN), 干扰素. IFN-α, IFN-β, IFN-γ Colony-stimulating factors(CSF), 集落刺激因子 Monocyte-CSF(M-CSF), Granulocyte-monocyte CSF(GM-CSF) Transforming growth factor(TGF), 转化生长因子 Chemokines ，趋化因子. IL Classification of cytokines

1.3 Immunological effects of cytokines

♥. The actions of cytokines are often Pleiotropic ( 多效性 )and Redundant （重叠性） Pleiotropic means the ability of one cytokine to act on different cell types. Redundant refers to the property of multiple cytokines having the same functional effects.

多效性 重叠性 协同性 拮抗性

♥. Cytokines often influence the synthesis and actions of other cytokines.

♥. Cytokine actions may be local and systemic. 自分泌 旁分泌 内分泌

♥. Cytokines initiate their actions by binding to specific membrane receptors on the target cells. ♥. External signals regulate the expression of cytokine receptors and thus the responsiveness of cells to cytokines.

♥. The cellular responses to most cytokines consist of changes in gene expression in target cells, resulting in the expression of new functions and sometimes in the proliferation of the target cells.

2. Functional Classification of Cytokines Mediators and regulators of innate immunity These cytokines are produced mainly by mononuclear phagocytes in response to infectious agents.

Mediators and regulators of adaptive immunity Produced mainly by T cells in response to specific recognition of antigens. Stimulators of hematopoiesis Produced by bone marrow stromal cells, leukocytes, and other cells.

3. Cytokine Receptors All cytokine receptors consist of one or more transmembrane proteins whose extracellular portions are responsible for cytokine binding and whose cytoplasmic portions are responsible for initiating intracellular signaling pathways. There are three major shared receptors in the class I cytokine receptor family: the common gamma chain (γc), gp130,and the common beta chain (βc).

4. Cytokines That Mediate and Regulate Innate Immunity

促炎因子

Bystander activation

IFN-α, IFNβ

脑垂体细胞

5. Cytokines That Mediate and Regulate Adaptive Immunity

Interleukin-2 (IL-2) and its receptor

Biological effects of IL-2

6. Cytokines That Stimulate Hematopoiesis

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