Derived
from the Greek words with “cyto” means cells and “kinos”
for movement the term cytokines came into existence. At the site of
inflammation, infection or any immune response the cellular communication is
possible through the cell signalling molecules called cytokines. These
signalling molecules initiate the immune cells homing at the site of trauma,
infection or any other immune reaction. There is no single classification of
cytokines, therefore, grouped in different ways. These molecules can be in a
form of glycoproteins, proteins or peptides. These are critical immune-modulating
agents that can modulate both innate immune response and adaptive immune
response.
The
important cytokines playing role in immune response against infection and
inflammation are interferon and interleukins.
Cells Involved
Nearly
all nucleated cells can possibly produce cytokines like IL-6 (Interleukin 6),
IL-1 (Interleukin 1) and TNF-α
(Tumour necrosis factor). Broad distributions of cytokines are endothelial
cells, lymphocytes like B- cells and T-cells, mast cells, stromal and
fibroblast cells etc.
The
immune-modulator molecules act on immune cells with receptors specific for them
and they act as ligands to the cells.
Classification
Based
on structural homogeneity cytokines can be grouped into four types:
1. A
family of cytokines with four bundles of helix and sub divided into 3 groups
such as IFN, IL-2, and 1L-10.
2. 2.
Family of IL-1 cytokines involves IL-18 and IL-1.
3. Family
of IL-17
4. Fourth
family includes super family of TGF-β
with TGF-β1, β2
and β3.
Functions
Cytokines
are important immune-modulatory glycoproteins or proteins molecules regulating
anti-inflammatory pathways. They are critically involved in the auto-immune
disorders oxidative stress derived responses, chronic inflammation as well as
other immune responses.
Receptors
Based
on the three dimensional structure, the cytokines are classified into following
groups:
1. IL-17R
(Interleukin Receptors)
2. Family
of seven transmembrane helix (GPCR, Chemokine receptor)
3. Interferon
family (IFN-β/ IFN-γ)
4. Growth
factors family
5. TNF
family
6. Ig
family
No comments:
Post a Comment