Cytokines.pptx by Taimoor Khan University of Swabi

biotechnology

1. Animal Biotechnology Semester 5 th Taimoor Khan

2. Cytokines Cytokines are signaling proteins that help control inflammation in your body. C hemical messengers Facilitate immune system (defense) against foreign substance, like viruses and bacteria , allergens.

3. 5–25  kDa size Due to their size, cytokines cannot cross the lipid bilayer of cells to enter the cytoplasm and therefore typically exert their functions by interacting with specific cytokine receptors on the target cell surface.

4. Cytokines are produced by a broad range of cells, including immune cells like; M acrophages , B lymphocytes, T lymphocytes M ast cells, Endothelial cells, F ibroblasts

5. Types Chemokines Interferons Interleukins Tumor Necrosis Factor (TNF)

6. Chemokines D irect immune cells toward places in your body where they can fight infection . Signaling proteins secreted by cells that induce directional movement of leukocytes, S timulate the migration of cells (inflammatory responses) A ctivation of host immune responses

7. Some chemokines control cells of the  immune system  during processes of immune surveillance, such as directing  lymphocytes  to the  lymph nodes  so they can screen for invasion of pathogens by interacting with  antigen-presenting cells  residing in these tissues.

8. Interleukins  expressed and secreted by  white blood cells (leukocytes). Immune response, modulate growth

9. Human genome encode < 50 interleukin. IL-4 , IL-5 , and IL-13  B-cell growth factors stimulation of B-cells by pathogens leads to increased expression of cytokine receptors . IL-2  plays a vital role in the proliferation and activation of T lymphocytes

10. Interferons  G roup of signaling proteins made and released by host cells in response to the presence of several viruses . V irus-infected cell will release interfe - r ons causing nearby   cells to heighten their anti-viral defenses.

11. Interferons properties IFN alpha IFN beta IFN gamma Cell sources Leukocytes Fibroblasts, leukocytes, epithelial cells T cells, NK cells Inducers Viruses, endotoxins, TNF alpha, IL 1 Double stranded RNA, IL 6 Antigen, polyclonal mitogen, IL 2, IL12 MOL. Weight ( KDa ) 18-20 23 20-25 Chromosomal location 9 9 12 Anti viral effect Yes Yes Yes (slower)

12. Tumor Necrosis Factor TNF acts as a pro-inflammatory cytokine, triggering the recruitment of immune cells such as neutrophils and macrophages, to the site of infection or injury. Enhance ability of immune cells to fight pathogens by releasing IL-6 and IL-1.

13. Tumor Necrosis factor TNF is used by the immune system for cell signaling when bind to a ligand. I nflammatory protein-- TNF is produced primarily by  macrophages  in response to  antigens , and activates inflammatory pathways through its two receptors TNFR1 TNFR2

14. TNFR1 (55-kDa) Expressed on most cell types. Signals-- Pro inflammatory and  apoptotic. TNFR2 (75-kDa) TNFR2 is restricted primarily to endothelial, epithelial, and subsets of immune cells. A nti-inflammatory and promotes cell proliferation.

15. Cytokines For M icrobial Infection Antiviral Cytokines  Interferons Interfere viral replication. All IFN utilizes same cell surface receptors , consequently having same antiviral , anti-proliferative activities.

16. Inflammatory Cytokines IL-1  inflammatory reactions Hematopoiesis TNF --> pro inflammatory Cytokine. TNF-α is a potent inducer of inflammation . TNF--- induces apoptosis . Vasodilation IL-6 

17. IL-6  D iscovered as antiviral substance in 1985. Pleotropic cytokine. Produce – predominantly by macrophages, B-lymphocytes, fibroblast. In response to exogenous injuries and polyclonal stimulant (IL-1, TNF).

18. Induces – Acute phase proteins Effects – pro-inflammatory and anti inflammatory.