BIOC39H3 Lecture Notes - Lecture 20: Type I Hypersensitivity, Antigen-Presenting Cell, Type Ii Hypersensitivity
8 Apr 2015
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Document Summary
Overreactions of the immune systems to harmless environmental antigens. Allergy: state of hypersensitivity induced by environmental antigens. Rise in prevalence of allergic diseases has continued for 50 years in industrialized countries. Feces of very small animals (house, dust mites) Described as immediate hypersensitivity as they occur immediately after exposure to antigen. Commonly caused by inhaled particulate antigens (plant pollens) Results from binding of antigen to ige bound to its fc receptor, principally on mast cells. Interaction causes the degradation of mast cells and the release of inflammatory mediators. Proteins or chemicals that chemically modify human proteins. Small, soluble proteins that are present in dried up particles derived from plants and animals. Once inhaled, the particles are trapped in the mucus bathing the epithelia of the airways and lungs, where they rehydrate and release the antigenic proteins. Proteins are presented by antigen presenting cells to cd4 t cells, initiating a th2 response.
