All of the following are mediators of inflammation except:
Ans. is 'c' i.e., Myeloperoxidase Myeloperoxidase is not an inflammatory mediator. It is an enzyme of neutrophil which catalyzes the conversion of Cl, Bf, and T, and SCN to the corresponding acids (HOCl, HOBr etc.). These acids are potent oxidants and help in destroying the invading organisms.Mediators of inflammationMediators are derived either from plasma or from cells.Plasma derived mediator's - These are present in plasma in precursor forms that must be activated usually by a series of proteolytic cleavage.Cell derived mediators - Cell-derived mediators are sequestered in intracellular granules that need to be secreted (e.g. histamine in mast cells) or are synthesized de novo.Summary of Mediators of acute inflammation*MediatorSourceVascular leakageChemotaxisOtherHistamine & serotoninMast cell, platelets+- BradykininPlasma substrate+-PainC3aPlasma protein via liver+-Opsonic fragmentC5aMacrophages++Leucocyte adhesion,ProstaglandinsMast cells, from membrane phospholipidProteinate other mediators Vasodilatation, pain, feverLeukotriene B4Leucocytes-+Leucocyte adhesion, activationLeukotriene C4, D4 e4leucocyte, Mast cells+-Bronchoconstriction, vasoconstrictionOxygen metabolitesleucocytes+"Endothelial damage, tissue damagePAFLeucocytes, mast cells++Bronchoconstriction, leucocyte primingIL-1 and TNFMacrophages, other-+Acute phase reactions, endothelial activationChemokinesLeucocytes, others-+Leucocyte activationNitric oxideMacrophages, endothelium++Vasodilation cytotoxicity* Role of mediators in different reactions of inflammation. VasodilationProstaglandins Nitric Oxide HistamineIncreased VascularVasoactive aminespermeabilityC3a and C5a Bradykinin leukotrienes C4, D4, F4 PAF Substance P Chemotaxis, leucocyte recruitment and activationC5a leukotriene B4 Chemokines II-1, TNF Bacterial productsFeverII-1, TNF ProstaglandinsPainProstaglandins, BradykininTissueNeutrophil and macrophagedamageLysosomal enzymes oxygen metabolites Nitric oxide
Tumour necrosis factor-a (TNF-a)
Interleukin-1
Myeloperoxidase
Prostaglandins
Cellular Pathology