MHC molecule

MHC molecule

 (ĕm′āch′sē′)
n.
Any of various polymorphic transmembrane proteins that are coded for by the genes of the major histocompatibility complex and that function in the immune system to present foreign antigens to T cells. Class I MHC molecules are found in most nucleated cells and present antigens originating intracellularly, such as virus fragments, to cytotoxic T lymphocytes. Class II MHC molecules are found in dendritic cells, macrophages, and other antigen-presenting cells and present antigens from extracellular pathogens, such as bacteria and parasites, to helper T cells.

[m(ajor) h(istocompatibility) c(omplex) molecule.]
References in periodicals archive ?
MHC Class I molecules present peptides derived from endogenous protein onto the surface of antigen-presenting cells whereas MHC Class II molecules is responsible for processing the exogenous antigens.[6] The antigens presented by MHC molecules can be recognized by T cells, thus initiating adaptive immune responses.[7] The differences of MHC molecule amino acid sequence result in distinct host epitope preference and response magnitude to the same antigen.
To develop a mouse model of T1D having reduced thymic insulin quantity, and also expressing the human class I MHC molecule HLA-A*02:01, we generated NOD.[[beta].sub.2][m.sup.KO].HHD.[Ins2.sup.het] mice.
However, only one MHC class II B locus was identified in Chinese long snout catfish (Shen et al., 2011).In mammals, MHC polymorphism is maintained over long times by positive (balancing) selection at the nonsynonymous sites specifying the PBR of the MHC molecule (Graser et al., 1996).
In addition, peptide residues immediately flanking the core region have been indicated to make contact with the MHC molecule outside of the binding groove and to contribute to MHC-peptide interaction [45].
Sometime along its treacherous evolutionary path, HCMV stole a class 1 MHC molecule from its host and modified it for supreme stealth.
We first considered the requirement that antigen-specific CTLs must respond to a peptide antigen exposed on the surface of APCs bound to a self class I MHC molecule. If there is an adverse indirect effect on cell-mediated immunity due to PRN exposure, it could result from altered antigen processing and presentation characteristics of the APC.
If an antigen receptor on a B-cell binds to a molecule on an antigen, the antigen will be internalized and a segment of the protein antigen will be presented by an MHC molecule to a T-helper cell.
Keys for methods: SM: sequence motif; SB: structure-based; MM: motif matrix; QAM: quantitative affinity matrix; SVM: support vector machine; ANN: artificial neural network; QSAR: quantitative structure-activity relationship model; combined: tool uses different methods including ANN and QAM, selecting the more appropriate method for each distinct MHC molecule. The table also indicates whether the tools predict quantitative binding affinity (A), supertypes (S), TAP binding (T), and proteasomal cleavage (P); marked with an X in the affirmative case.
In the newly discovered compartment that remained, enzymes began to break down the antigen, probably with an MHC molecule standing by to grab the fragment it wants.
It snows that another type of MHC molecule, MHC-II, does a similar job but in a different way, says Lawrence J.
"Our understanding of the MHC molecule has advanced enormously from this set of papers," says lan A.