A genetic locus in vertebrates consisting of numerous histocompatibility genes controlling cell surface immune response determinants and components of the complement system. There are three MHC class I proteins found at the plasma membrane of most cell types, and at least six MHC class II proteins found on the surface of antigen-presenting cells (T cells, B cells and macrophages). They occur in many alternative allelic forms and, depending on their amino acid structure, bind particular peptides, e.g. processed viral antigens, at their distal tip to form a peptide-MHC complex. This complex is recognized by T-cell receptors and their co-receptors CD4 for MHC class II (helper T cells) or CD8 for MHC class I (cytotoxic T cells). Positive selection of developing T cells in the thymus by 'self' MHC molecules results in mature T cells that only recognize the foreign peptides if they are presented by a 'self' MHC protein. This is termed 'MHC restriction'. In different vertebrates different abbreviations are used to describe the MHC system, e.g. chicken (B), dog (DLA), guinea pig (GPLA), human (HLA), mouse (H2) and rat (Rt1). See also human leukocyte antigens.
Brutkiewicz RR and Welsh RM (1995) J Virol 69, 3967
Makonde virus Synonym for Uganda S virus.
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