In immunology

Immunology

Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders ; the...

, activation is the transition of leucocytes and other cell types involved in the immune system

Immune system

An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

. On the other hand, deactivation is the transition in the reverse direction. This balance is tightly regulated, since a too small degree of activation causes susceptibility to infection

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

s, while, on the other hand, a too large degree of activation causes autoimmune diseases.

Factors

Activation and deactivation results from a variety of factors, including cytokines, soluble receptors, arachidonic acid

Arachidonic acid

Arachidonic acid is a polyunsaturated omega-6 fatty acid 20:4.It is the counterpart to the saturated arachidic acid found in peanut oil, Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6).It is the counterpart to the saturated arachidic acid found in peanut oil,...

 metabolites, steroids, receptor antagonists, adhesion molecules, bacterial products and viral products.

Overview of activating and deactivating factors.

	Activation	Deactivation
Cytokines	IFN-γ GM-CSF M-CSF IL-6 Interleukin 6 Interleukin-6 is a protein that in humans is encoded by the IL6 gene.IL-6 is an interleukin that acts as both a pro-inflammatory and anti-inflammatory cytokine. It is secreted by T cells and macrophages to stimulate immune response, e.g. during infection and after trauma, especially burns or other... TNF-α MIF Macrophage migration inhibitory factor Macrophage migration inhibitory factor also known as glycosylation-inhibiting factor , L-dopachrome isomerase, or phenylpyruvate tautomerase is a protein that in humans is encoded by the MIF gene.- Structure :... CCL2 CCL2 For the ICAO airport code see Candle Lake Airpark, for the diradical compound see Dichlorocarbene.Chemokine ligand 2 also known as monocyte chemotactic protein-1 or small inducible cytokine A2 is a protein that in humans is encoded by the CCL2 gene. CCL2 is a small cytokine belonging to the CC...	IL-4 Interleukin 4 Interleukin-4, abbreviated IL-4, is a cytokine that induces differentiation of naive helper T cells to Th2 cells. Upon activation by IL-4, Th2 cells subsequently produce additional IL-4. The cell that initially produces IL-4, thus inducing Th0 differentiation, has not been identified, but recent... IL-10 Interleukin 10 Interleukin-10 , also known as human cytokine synthesis inhibitory factor , is an anti-inflammatory cytokine. In humans IL-10 is encoded by the IL10 gene.... IL-13 Interleukin 13 Interleukin 13 is a protein that in humans is encoded by the IL13 gene. IL-13 is cytokine secreted by many cell types, but especially T helper type 2 cells, that is a mediator of allergic inflammation and disease.-Functions:... TGF-β
Soluble receptors		sIL-1R sIL-6R sTNFR sCD14
Arachidonic acid Arachidonic acid Arachidonic acid is a polyunsaturated omega-6 fatty acid 20:4.It is the counterpart to the saturated arachidic acid found in peanut oil, Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6).It is the counterpart to the saturated arachidic acid found in peanut oil,...  metabolites	PGE2 LTB4
Steroids		Corticosteroids
Receptor antagonists		IL-1Ra
Adhesion molecules	β2-integrins Fc receptors CD14 CD14 Cluster of differentiation 14 also known as CD14 is a human gene.The protein encoded by this gene is a component of the innate immune system. CD14 exists in two forms. Either it is anchored into the membrane by a glycosylphosphatidylinositol tail or it appears in a soluble form... P-selectin P-selectin P-selectin is a cell adhesion molecule on the surfaces of activated endothelial cells, which line the inner surface of blood vessels, and activated platelets... CD45 CD45 Protein tyrosine phosphatase, receptor type, C also known as PTPRC is an enzyme that, in humans, is encoded by the PTPRC gene. PTPRC is also known as CD45 antigen , which was originally called leukocyte common antigen.- Function :The protein encoded by this gene is a member of the protein tyrosine...
Bacterial products	LPS Lipopolysaccharide Lipopolysaccharides , also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals.-Functions:LPS is the major... fMetLeuPhe
Viral products	dsRNA	BCRF1 (IL-10 Interleukin 10 Interleukin-10 , also known as human cytokine synthesis inhibitory factor , is an anti-inflammatory cytokine. In humans IL-10 is encoded by the IL10 gene.... -homologue) T2 (sTNFR-homologue) M-T7 (sINF-γR-homologue)