Major Histocompatibility Complex (MHC)


The major histocompatibility complex (MHC) contains the most diverse genes known in vertebrates, the class I and II loci. These highly polymorphic genes encode cell surface receptors that play a central role in controlling immunological self/nonself recognition, and subsequently, tissue rejection, autoimmunity and immune responses to infectious diseases. The polymorphisms of MHC genes have been maintained by natural selection over long periods of evolutionary time.

Keywords: genetic diversity; immunology; host–parasite coevolution; sexual selection

Figure 1.

The genetic architecture of the MHC in humans and house mice.

Figure 2.

Antigen presentation triggers immune effectors. (a) Cytotoxic T cells recognize foreign peptides presented by class I MHC molecules on infected cells. Helper T cells recognize foreign peptides presented by class II MHC molecules presented by (b) macrophages and (c) B lymphocytes. TCR, T‐cell receptor. Enlargements show immunological synapse.

Figure 3.

(a) A class I MHC molecule and (b) the antigen‐binging site of a class I MHC molecule looking down into the groove.

Figure 4.

MHC genes belong to the immunoglobulin multigene superfamily, which includes T‐cell receptors and antibodies, suggesting that these molecules evolved from a common ancestor.


Further Reading

Bernatchez L and Landry C (2003) MHC studies in nonmodel vertebrates: what have we learned about natural selection in 15 years?. Journal of Evolutionary Biology 16: 363–377.

Carrington M, Nelson GW, Martin MP, et al. (1999) HLA and HIV‐1: heterozygote advantage and B*35‐Cw*04 disadvantage. Science 283: 1748–1752.

Kulski JK, Shiina T, Anzai T, Kohara S and Inoko H (2002) Comparative genomic analysis of the MHC: the evolution of class I duplication blocks, diversity and complexity from shark to man. Immunological Reviews 190: 95–122.

Penn DJ (2002) The scent of genetic compatibility: sexual selection and the major histocompatibility complex. Ethology 108: 1–21.

Sette A, Sidney J, Livingston BD, et al. (2003) Class I molecules with similar peptide‐binding specificities are the result of both common ancestry and convergent evolution. Immunogenetics 54: 830–841.

Trachtenberg E, Korber B, Sollars C, et al. (2003) Advantage of rare HLA supertype in HIV disease progression. Nature Medicine 9: 928–935.

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How to Cite close
Penn, Dustin J, and Ilmonen, Petteri(Sep 2005) Major Histocompatibility Complex (MHC). In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0003986]