Changes

MHC class I is expressed on virtually all nucleated cells and consists of a membrane-associated heavy chain bound non-covalently with a secreted light chain. The heavy chain is made up of three distinct extracellular protein domains - α1, α2 and α3. The heavy chain C - terminus is cytoplasmic.

MHC class I is expressed on virtually all nucleated cells and consists of a membrane-associated heavy chain bound non-covalently with a secreted light chain. The heavy chain is made up of three distinct extracellular protein domains - α1, α2 and α3. The heavy chain C - terminus is cytoplasmic.

The light chain is known as β2-microglobulin and is similar in structure to one of the heavy chain domains. It is not membrane associated but binds to the α3-domain of the heavy chain

The light chain is known as β2-microglobulin and is similar in structure to one of the heavy chain domains. It is not membrane associated but binds to the α3-domain of the heavy chain. This domain activates [[T Cell Differentiation|T helper cells]] through the interaction with the CD4⁺ on the cell surface of the TH cells.

[[Image:MHC I Structure.jpg|thumb|right|200px| Structure of MHC I molecule - Copyright Prof Dirk Werling DrMedVet PhD MRCVS]]

[[Image:MHC I Structure.jpg|thumb|right|200px| Structure of MHC I molecule - Copyright Prof Dirk Werling DrMedVet PhD MRCVS]]