Type IV Hypersensitivity reaction and it’s mechanism

Type IV hypersensitivity reaction result from inappropriate T-cell activation. It takes at least 3 days to develop its action for this reason it is also called delayed type hypersensitivity (DTH). It is the only hypersensitivity category, that is purely cell mediated rather than antibody mediated. Mentioned disorders: Contact dermatitis, Chronic transplant rejection, Multiple sclerosis, Granuloma …

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Type III Hypersensitivity Reaction and it’s Mechanism

In type III hypersensitivity reaction, antigen-antibody complex deposited on host cells induces complement fixation and enhance inflammatory reaction. It is mainly mediated by Ig-G antibodies complement protein and neutrophils. The reaction of antibodies with the soluble antigens, generates immune complexes. Generally, these reactions facilitate the clearance of antigens by phagocytes But some times the presence …

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