Sunday, April 18, 2010

HYPERSENSITIVITY

This past week in immunology class the word hypersensitivity was mentioned in relation to our discussion on T cell activation and as a part of T helper 1 responsibility. I have also heard the word a few times again at work as well. With this continuous occurrence I obtain a better understanding for hypersensitivity and what it has to do with Immunology!

What is Hypersensitivity?
Hypersensitivity is the immune system's inappropriate response to the presence of antigen. There are about 4 different types of characterized hypersensitivity, type 1, type 2, type 3, and type 4.

Type 1; Immediate Hypersensitivity-A rapid antibody-mediated reaction that is responsible for allergies to penicillin, molds, insect bites and other known allergies.

Type 2; Cytotoxic Hypersensitivity-Antibody-mediated reactions that involve more specifically IgG. It includes the involvement of K cells which are involved in antibody-dependent cell-mediated cytotoxicit. Antibodies are specific for self antigens. This hypersensitivity includes Pemphigus, Autoimmune hemolytic anemia (AHA), and Goodpasture's syndrome.

Type 3; Immune Complex Hypersensitivity-An example is serum sickness. It involves the interaction between circulating antibodies and free antigen.

Type 4; Delayed Hypersensitivity-Cell mdiated antibody independent immune memory response responsible for grave's disease, systemic lupus erythematosus.

http://www.cehs.siu.edu/fix/medmicro/hyper.htm

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