免疫学学习笔记-3 Cytokines and Interferons

CYTOKINES : ILs, INFs, TNFs, CSFs and Chemokines

How the communication among immune cells takes place?

Cytokines – small soluble molecules

·Produced and secreted by wide variety of cells

·Act as intercellular mediators

·Cytokines bind to specific receptors on the surface of other cells (cytokine receptor).

·Alter the activity of the cell

oA cell may prepare to divide

oUndergo growth and differentiation

oSecrete its own cytokines

·Hormone-like substances 类激素物质

·Soluble molecules, some are membrane bound molecules

·Chemically they can be protein or glycoprotein 糖蛋白

·Molecular mass is less than 30 kDa 分子量

·Have short half-life

·Mostlyact over a short-distance (autocrine and paracrine)

·Effectively at low concentrations, because of specific high-affinity cytokine receptors

Classification of cytokines

·Interleukins     白细胞介素

·Tumer necrosis factor   肿瘤坏死因子

·Interferons      干扰素

·Colony-stimulating factors (CSFs)   集落刺激因子

·Chemokines    趋化因子

Interleukins

·Cytokines produced by one leukocyte acting on another leucocyte. 一种白细胞产生的细胞因子作用于另一种白细胞。

·Though cells other than leukocytes may also use interleukins. 尽管白细胞以外的细胞也可能使用白细胞介素。

·About35 interleukins have been identified

·They are named interleukin (IL) followed by number which represents sequence in which they were discovered (IL-1 to IL-35)

·IL-2: Growth and Activation of T cells

·IL-4: B cell differentiation into plasma cells

Tumer necrosis factor

·TNFs are produced by Mast cells, Macrophages and T cells

·They are often firmly archored into the cell membrane.它们通常牢固地固定在细胞膜上。

·They regulate immune responses and inflammation

·Responsible for apoptosis of many cell types

·TNF-α: Activation of Neutrophils

Interferons

·So named because of their ability to interfere with viral replication

·Two types of IFNs

oType I interferons: IFN-α, IFN-β

Produced in response to viral infections

oType II interferons: IFN-γ

Increases phagocytosis by macrophages

Colony-stimulating factors (CSFs)

·Essential for the growth and differentiation of immature leukocytes in the bone marrow i.e. red blood cells, monocytes, granulocytes and lymphocytes.

·Ensure that the body is supplied with sufficient white blood cells of all types.

·Three types of CSFs

·M-CSF (Source: T cell): Monocyte colony-stimulating factor – Growth of cells of monocyte lineage

·GM-CSF (Source: T cell and Macrophage): Granulocyte Macrophage colony-stimulating factor – Growth and Differentiation of dendritic cells

·G-CSF (Source: Monocyte): Granulocyte colony-stimulating factor – Differentiation and Development of neutrophils

Chemokines

• Act as chemo-attractants and signal leukocytes to move. 作为化学引诱剂并发出白细胞移动信号

Interferons: INF-α, INF-β and INF-γ

Type II interferons: IFN-γ

·Produced by activated T lymphocytes and NK cells.

·Stimulate the activity of macrophages

·Also known as Macrophages activation factor.