MHC Molecules: Difference between revisions
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Revision as of 14:43, 22 November 2010
MHC Molecules play a key role in the presentation of antigens. The foreign protein must be processed into a peptide before it can be presented by MHC. This processing occurs in the Proteasome of the Cell. There are 2 types of MHC Molecule; Class 1 MHC & Class 2 MHC.
MHC Class 1
MHC Class 1 molecules are expressed in all nucleated cells. These are involved in the presentation of endogenous antigens (those found intracellularly). Presentation of these endogenous antigens is recognised by Cytotoxic T cells that destroy the antigen via a mechanism involving the use of Granzyme and Perfornin.
MHC Class 2
MHC Class 2 are expressed in professional antigen presenting cells such as macrophages and B Cells. They present exogenous antigens (those made outside the cell). They bind peptides 18-20 amino acids long.