Class I histocompatibility antigens

Mr 11,800) globular protein located on the surface of virtually all nucleated cells. It is closely related to the class I histocompatibility antigens which consist of a heavy, variable chain and a hght chain that hinds to the heavy chain domain nearest to the cell membrane. The light chain consists of the molecule. Due to its... 

Bjorkman PJ, Saper MA, Samraoui B, Bennett WS, Strominger JL, Wiley DC Structure of the human class I histocompatibility antigen, HLA-A2. Nature 1987 329 506-512. 

B14. Bjorkman, P. J., Saper, M. A., Samraoui, B., Bennett, W. S., Strominger, J. L., and Wiley, D. C. The foreign antigen binding site and T cell recognition regions of class I histocompatibility antigens. Nature (London) 329, 512-518 (1987). 

There are several examples of parts of membrane proteins determined crystallographically. Here, a protein anchored in the membrane is clipped to provide just the hydrophilic domain for crystallisation. These studies were of cytochrome b5 (Mathews, Argos and Levine 1972), haemagglutinin (Wilson etal 1981) and neuraminidase (Varghese, Laver and Colman 1983) from influenza virus and the human class I histocompatibility antigen, HLA-A2 (Bjorkman et al 1987). 

York lA, Goldberg AL, Mo XY, Rock KL Proteolysis 73 and class I major histocompatibility complex antigen presentation. Immunol Rev 1999 172 49-66. 

Paulsson, K. (2004) Evolutionary and functional perspectives of the major histocompatibility complex class I antigen-processing machinery. Cell. Mol. Life Sci. 61, 2446-2460. 

Bonifaz L. Bonnyay D, Mahnke K, Rivera M, Nussenzweig MC, Steinman RM Efficient targeting of protein antigen to the dendritic cell receptor DEC-205 in the steady state leads to antigen presentation on major histocompatibility complex class I products and peripheral CDS4- T cell tolerance. J Exp Med 2002 196 1627-1638. 

The major histocompatibility complex (MHC) is, in fact, a set of genes which code for three classes of proteins -class I, class II and class III. The class I proteins are involved in identifying cells that are infected with a virus. Class II proteins are involved in the interactions between Th cells and antigens. Class III proteins are the complement proteins. Although the name major histocompatibility complex actually refers to the genes,... 

To initiate a T-cell immune response, antigen presenting cells have to display antigenic peptides com-plexed with the major histocompatibility complex (MHC) on their cell surface. The T-cell receptor of CDS cells is specific for the peptide-MHC class I complex while the CD4 cell receptor binds the peptide-MHC class II complex. This binding of the peptide-MHC II complex stimulates CD4 cell proliferation and subsequent lymphokine release. This CD4 cell response can initiate a delayed hypersensitivity reaction. However CD4 activation and the production of various lymphokines is also needed for the generation of cytotoxic T-cells and for the differentiation of plasma cells from B-lymphocytes and the antibody response by these plasma cells. For their role in also the humoral immune response CD4 cells are called T-helper cells. 

APC, antigen-presenting cell and, class I and II major histocompatibility complex (MHC) antigens o and , peptides from degraded antigen bound to MFIC molecules ... 

The major histocompatibility complex (MHC) is part of the system that codes for molecules important in immune recognition, including graft rejection. MHC class I and II molecules present antigen fragments to T-lymphocytes. For example, class I molecules bind viral proteins and present them to the CD8+ T cells. Exogenous antigens such as proteins taken into the cell by endocytosis are processed within the cell and presented to CD4+ cells. 

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