1. Cytokines Dr.Marián Sabol, PhD.
P.J. Šafárik University, Medical Faculty,
Institute of Medical Microbiology
Tr. SNP 1, Košice, Slovakia

2. 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.

3. 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.

4. Properties of cytokines
Autocrine,
Paracrine and
Endocrine Action

5. Cytokine network Pleiotropy, Redundancy, Synergy, Antagonism
of Cytokines
REDUNDANCY
SYNERGY
ANTAGONISM

6. Cytokine network
Cascade Induction
of Cytokines

7. Inflammatory response
Fibroblasts
Endothelial cells
TNF
TNF
IL-1
TGF-
PDGF
IL- 1
Hypotalamus
Mph
IL-1,6
TNF-
Antigen
Neutrophil
Hematopoiesis
IL- 1, 6, 11, 12
TNF, CSFs
IL- 1,6,8,
IL-10,12,15
IFN ,
TNF- 
IL-8, TNF-
Stem cell
IL-3,4.10,13
IFN-, 
TNF-
Mast
cell
IL-3,6,7
GM-CSF
Antigen
IL- 3,4,10
Resting T
cell
Eosinophils
Resting
B cell
IL –10,4
IL- 3,5
IL-2
IL-12 (APC)
IL-15
IL-4
IL-2
IL-2
IL-2
IFN-
IL-15 Th
IL-2,4,5,13
TGF-
IFN-
IL-2
IFN-
TGF-
IL -2
IL-2 NK
IL-12
(via APC)
Clonal
expansion
IL-6
LAK
Activated
B cell
T cell
Plasma Cell

12. Regulation of TH Subsets by Cytokines
Th1 / Th2
Regulation of TH Subsets by Cytokines

13. 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, IFNg and TNFb)
- IFNg also inhibits the expansion of the TH2 population.

14. 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.