What is type 3 allergy?
Immunology. Type III hypersensitivity occurs when there is accumulation of immune complexes (antigen-antibody complexes) that have not been adequately cleared by innate immune cells, giving rise to an inflammatory response and attraction of leukocytes. Such reactions may progress to immune complex diseases.
What causes type III hypersensitivity?
Type III hypersensitivity is caused by circulating immunocomplexes (see Fig. 2-29C) and is typified by serum sickness (a drug reaction in which multimeric drug-antibody aggregates form in solution). Preformed immunocomplexes deposit in various vascular beds and cause injury at these sites.
What is the definition of Type III hypersensitivity?
Type III hypersensitivity Type III, or immune-complex, reactions are characterized by tissue damage caused by the activation of complement in response to antigen-antibody (immune) complexes that are deposited in tissues.
When does an immediate hypersensitivity reaction occur?
Type I, II, and III hypersensitivity reactions are known as immediate hypersensitivity reactions because they occur within 24 hours of exposure to the antigen or allergen. Immediate hypersensitivity reactions are predominantly mediated by IgE, IgM, and IgG antibodies.
Can a monoclonal antibody cause type III hypersensitivity?
Monoclonal and polyclonal antibodies prepared from rabbit, horse, or mouse serum-like anti-thymocyte globulin, OKT-3, have been found to cause type III hypersensitivity reaction. Serum sickness-like reaction (SSLR) can be seen with synthetic monoclonal antibodies (chimeric protein).
How long does it take for Type II hypersensitivity to develop?
The tissue damaging mechanisms are similar to those described for the antigen-antibody complexes that form in type II responses. The response times of types II and III hypersensitivity reactions are slower than that of type I reactions; they typically develop 3–6 h after exposure to antigen.