type IV hypersensitivity
A delayed hypersensitivity response (it appears 24 to 48 hours after antigen exposure). It results from the binding of antigen to activated T-lymphocytes, which then release cytokines and trigger inflammation and macrophage attacks that damage tissue. Type IV hypersensitivity is seen in contact dermititis from poison ivy, leprosy, and tertiary syphilis.

Microbiology. . 2009.

Look at other dictionaries:

  • Type IV hypersensitivity — Classification and external resources MeSH D006968 Type IV hypersensitivity is often called delayed type hypersensitivity as the reaction takes two to three days to develop. Unlike the other types, it is not antibody mediated but rather is a type …   Wikipedia

  • type IV hypersensitivity — hypersensitivity initiated by antigen specific T lymphocytes; unlike forms mediated by antibodies, it takes one or more days to develop and can be transferred by lymphocytes but not by serum. The term is often equated with delayed… …   Medical dictionary

  • type IV — a reaction of cell mediated immunity, the immune response being initiated by antigen specific T lymphocytes; in contrast to the reactions of immediate hypersensitivity, reactions take one or more days to develop and can be transferred by… …   Medical dictionary

  • Hypersensitivity pneumonitis — Classification and external resources Micrograph of hypersensitivity pneumonitis. Lung biopsy. Trichrome stain …   Wikipedia

  • Type 4 — or Type Four may refer to: *Volkswagen Type 4 – a four door saloon *Type Four chassis – a front wheel drive car chassis *Type 4 encryption – an encryption algorithm *Type IV collagen a class of collagen *Type 4 Hypersensitivity a class of… …   Wikipedia

  • hypersensitivity — In immunology, a state of excessive and potentially damaging immune responsiveness as a result of previous exposure to antigen. If the hypersensitivity is of the immediate type (antibody mediated), then the response occurs in minutes; in delayed… …   Dictionary of molecular biology

  • hypersensitivity — Abnormal sensitivity, a condition in which there is an exaggerated response by the body to the stimulus of a foreign agent. See allergy. contact h. 1. SYN: contact dermatitis. 2. SYN: delayed reaction. delayed h. 1 …   Medical dictionary

  • contact hypersensitivity — type IV hypersensitivity produced by contact of the skin with a chemical substance having the properties of an antigen or hapten, the resulting skin condition being allergic contact dermatitis …   Medical dictionary

  • cell-mediated hypersensitivity reaction — type IV hypersensitivity r …   Medical dictionary

  • T cell–mediated hypersensitivity reaction — type IV hypersensitivity r …   Medical dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”