MHC Molecules: Difference between revisions
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MHC Class 2 are expressed in professional [[Antigen presenting cells|antigen presenting cells]] such as [[Macrophage|macrophages]] and [[B Cells|B Cells]]. They present exogenous [[Antigens|antigens]] (those made outside the cell). They bind peptides 18-20 [[Amino acids|amino acids]] long. | MHC Class 2 are expressed in professional [[Antigen presenting cells|antigen presenting cells]] such as [[Macrophage|macrophages]] and [[B Cells|B Cells]]. They present exogenous [[Antigens|antigens]] (those made outside the cell). They bind peptides 18-20 [[Amino acids|amino acids]] long. | ||
Unlike MHC Class 1 receptors, these molecules have two alpha and two beta subunits, with transmembrane spanning regions from alpha-2 and beta-2. The alpha-1 and beta-1 subunits | Unlike MHC Class 1 receptors, these molecules have two alpha and two beta subunits, with transmembrane spanning regions from alpha-2 and beta-2. The alpha-1 and beta-1 subunits form an anitgen presenting site. | ||
Revision as of 14:21, 19 October 2012
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 1 molecules have 3 alpha subunits and 1 beta microglobin subunit. Both alpha 1 and 2 form the antigen presenting region of the molecule. MHC class 1 has only one transmembrane domain that anchors it into the cell membrane.
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.
Unlike MHC Class 1 receptors, these molecules have two alpha and two beta subunits, with transmembrane spanning regions from alpha-2 and beta-2. The alpha-1 and beta-1 subunits form an anitgen presenting site.