SHORT NOTE: CYTOKINES

SHORT NOTE: CYTOKINES
Cytokines are bioactive hormones, normally glycoproteins, which exercise a wide variety of biological effects on those cells which express the appropriate receptors. Cytokines are designated by their cellular origin such that

Ø      Monokines include those interleukins produced by macrophages/ monocytes,

Ø      lymphokines include those interleukins produced by lymphocytes.

Ø      Interleukins is used for cytokines which mostly influence cellular interactions.

All cytokines are cyto-regulatory proteins with molecular weights under 60 kDa (in most cases under 25 kDa). They are produced locally, have very short half-lives (a matter of seconds to minutes), and are effective at picomolar concentrations. The effects of cytokines may be paracrine (acting on cells near the production locus), or autocrine (the same cell both produces, and reacts to, the cytokine). By way of interaction with highly specific cell surface receptors, cytokines can induce cell-specific or more general effects (including mediator release, expression of differentiation molecules and regulation of cell surface molecule expression). The functions of cytokines are usually pleiotropic, in that they display a number of effects of the same, or of a different, nature on one or more cell types. Below is a summary of cytokine functions:

·        Promotion of inflammation: IL-1, IL-6, TNFα, chemokines (e.g., IL-8).

·         iinhibition of inflammation: IL-10, TGFß.

·         Promotion of hematopoiesis: GM-CSF, IL-3, G-CSF, M-CSF, IL-5, IL-7.

·         Activating B cells: CD40L, IL-6, IL-3, IL-4.

·         Activating T cells: IL-2, IL-4, IL-10, IL-13, IL-15.

·         Anti-infectious: IFNα, IFNß, IFNγ, TNFα.

·         Anti-proliferative: IFNα, IFNß, TNFα, TGFß.