major histocompatibility complex
noun
plural major histocompatibility complexes
: a group of genes in mammals that code for cell-surface polymorphic glycoprotein molecules which display antigenic peptide fragments for T cell recognition and aid in the ability of the immune system to determine self from nonself
Note: The genes of the major histocompatibility complex and the molecules they determine are grouped into 2 classes. Glycoprotein molecules of class I are expressed on all nucleated cells and are recognized by CD8 on the surface of cytotoxic T cells. Glycoprotein molecules of class II are restricted to antigen-presenting cells and are recognized by CD4 on the surface of helper T cells.
—often used before another nounmajor histocompatibility complex molecules
—abbreviation MHC
compare HLA
Examples of major histocompatibility complex in a Sentence
Recent Examples on the Web
One striking finding was a hard sweep on a region of chromosome 6 called major histocompatibility complex class III, or MHC III, in ancient Anatolians.
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Kermit Pattison, Scientific American, 20 May 2025
Scientists have long known, for example, that children inherit a wider variety of immune defenses when their parents differ greatly in a group of genes called the major histocompatibility complex (MHC).
—Arthur C. Brooks, The Atlantic, 10 Feb. 2022
Finally, in Orf8, which downregulates the major histocompatibility complex (MHC-I), the researchers note H17Y and G8stop.
—William A. Haseltine, Forbes, 22 Oct. 2021
The two year old Patient 2 was seeking the same treatment for another rare immune disease, major histocompatibility complex class II deficiency, which is considered a variant of SCID.
—Rebecca Kreston, Discover Magazine, 28 Apr. 2016
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Kermit Pattison, Scientific American, 20 May 2025
Scientists have long known, for example, that children inherit a wider variety of immune defenses when their parents differ greatly in a group of genes called the major histocompatibility complex (MHC).
—Arthur C. Brooks, The Atlantic, 10 Feb. 2022
Finally, in Orf8, which downregulates the major histocompatibility complex (MHC-I), the researchers note H17Y and G8stop.
—William A. Haseltine, Forbes, 22 Oct. 2021
The two year old Patient 2 was seeking the same treatment for another rare immune disease, major histocompatibility complex class II deficiency, which is considered a variant of SCID.
—Rebecca Kreston, Discover Magazine, 28 Apr. 2016
Cite this Entry
“Major histocompatibility complex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/major%20histocompatibility%20complex. Accessed 4 Nov. 2025.
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