Post on 18-Jan-2016
Cytokines
Dr.Marián Sabol, PhD.
P.J. Šafárik University, Medical Faculty, Institute of Medical MicrobiologyTr. SNP 1, Košice, Slovakia
Definition
-Low molecular non-antibody proteins
-Secreted by leukocytes and some non-leukocytic cells
- Act as intercellular mediators
- They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialised glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.
Functions of Cytokines
1.Development of cellular and humoral immune responses
2.Induction of the inflammatory response
3.Regulation of hematopoiesis
4.Control of cellular proliferation and differentiation
5. Healing of wounds
* Although the immune response to a specific Ag includes the production ofd of cytokines, cytokines act in an Ag-nonspecific manner.
Properties of cProperties of cytokinesytokines
Autocrine,
Paracrine and
Endocrine Action
Cytokine Cytokine networknetwork
Pleiotropy,
Redundancy,
Synergy,
Antagonism
of Cytokines
PLEIOTROPY
REDUNDANCY
ANTAGONISM
SYNERGY
Cytokine Cytokine networknetwork
Cascade Induction
of Cytokines
Plasma Cell
Inflammatory response
Clonalexpansion
T cell
LAK
NK
ActivatedB cell
Mast cell
Stem cell
Hematopoiesis
Endothelial cellsFibroblasts
Hypotalamus
Neutrophil
Antigen
RestingB cell
Mph
Resting T cell Eosinophils
Th
TNF IL-1
TGF- PDGF
TNF IL- 1
IL- 1, 6, 11, 12TNF, CSFsIL- 1,6,8,
IL-10,12,15IFN , TNF-
Antigen
IL-3,6,7GM-CSFIL- 3,4,10
IL- 3,5
IL-2
IL-2,4,5,13TGF-IFN-
IL-4
IL –10,4
IL -2 TGF-
IL-6
IL-3,4.10,13IFN-, TNF-
IL-8, TNF-
IL-1,6 TNF-
IL-2 IFN- IL-15
IL-2 IL-12 (APC) IL-15 IL-2
IL-2
IL-12(via APC)
IL-2 IFN-
Th1Th1 / / Th2Th2
Regulation of TH Subsets by Cytokines
TH1 Response
-cell-mediated functions (e.g., delayed-type hypersensitivity and activation of TC cells)
-Production of IgG3, IgG1, IgG2 (opsonization and C activation).-Excessive inflammation and tissue injury.- Target: viral infections and intracellular pathogens. ( IL-2, IFNand TNF)
- IFN also inhibits the expansion of the TH2 population.
TH2 Response
-Stimulates eosinophil activation and differentiation
- Provides help to B cells, and promotes the production
of relatively large amounts of IgM, IgE, and IgG4
-Supports allergic reactions.
The production of Il-4, IL-5 and IL-10 promotes the function of IgE and eosinophils on the anti-helminth (round worm) immunity.