major histocompatibility complex

(noun)

MHC is a cell surface molecule that mediate interactions of immune cells with other leukocytes or body cells. MHC determines compatibility of donors for organ transplants as well as one's susceptibility to an autoimmune disease. In humans, MHC is also called human leukocyte antigen (HLA).

Related Terms

Examples of major histocompatibility complex in the following topics:

  • T Cell Receptors

    • T lymphocytes have a dual specificity: they recognize polymorphic residues of self major histocompatibility complex (MHC) molecules, which accounts for their MHC restriction; they also recognize residues of peptide antigens displayed by these MHC molecules, which is responsible for their specificity.
    • MHC molecules and peptides form complexes on the surface of antigen presenting cells (APCs).
    • The receptor that recognizes these peptide-MHC complexes is called the T Cell Receptor (TCR).
    • The physiologic role of some accessory molecules is to deliver signals to the T cells that function in concert with signals from the TCR complex to fully activate the cell.
    • The recognition of peptide-MHC complexes is mediated by CDRs formed by both the alpha and beta chains of the TCR.

  • Clonal Selection and Tolerance

    • The theory that self-tolerance is 'learned' during lymphocyte development was a major conceptual contribution to immunology.
    • Positive selection ensures maturation of T cells whose receptors bind weakly to self major histocompatibility complex molecules.

  • Superantigens

    • Then the macrophage takes parts of the broken-down invader or other molecules that it ingested and posts the fragments on the outside of the cell using a major histocompatibility complex (MHC) to hold the fragment.

  • MHC Polymorphism and Antigen Binding

    • Major histocompatibility complex (MHC) is a cell-surface molecule encoded by a large gene family in all vertebrates.
    • The human leukocyte antigen (HLA) system is the name of the major histocompatibility complex (MHC) in humans.

  • Type IV (Delayed Cell-Mediated) Reactions

    • It also plays a major role in transplant rejection.
    • CD4+ helper T cells recognize antigen in a complex with Class 2 major histocompatibility complex.

  • Cytomegalovirus Infections

    • Major areas of risk of infection include prenatal or postnatal infants and immunocompromised individuals, such as organ transplant recipients, persons with leukemia, or those infected with human immunodeficiency virus (HIV).
    • CMV persists in the host because the viral genome encodes multiple proteins that interfere with major histocompatibility complex (MHC) class I presentation of viral antigens.

  • Interferons

    • Based on the type of receptor through which they signal, human interferons have been classified into three major types:
    • Interferon type III: These signal through a receptor complex consisting of IL10R2 (also called CRF2-4) and IFNLR1 (also called CRF2-12).
    • Another function of interferons is to upregulate major histocompatibility complex molecules, MHC I and MHC II, and increase immunoproteasome activity.
    • By interacting with their specific receptors, IFNs activate signal transducer and activator of transcription (STAT) complexes.
    • Binding of ISGF3 and other transcriptional complexes activated by IFN signaling to these specific regulatory elements induces transcription of those genes.

  • Cytotoxic Autoimmune Reactions

    • Three main sets of genes are suspected in many autoimmune diseases: immunoglobulins, T-cell receptors and the major histocompatibility complexes (MHC).
    • The contributions of genes outside the MHC complex remain the subject of research both in animal models of disease (Linda Wicker's extensive genetic studies of diabetes in the NOD mouse), and in patients (Brian Kotzin's linkage analysis of susceptibility to SLE).
    • HLA-DR is a MHC class II cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21.31.
    • The complex of HLA-DR and its ligand, a peptide of 9 amino acids in length or longer, constitutes a ligand for the T-cell receptor (TCR).

  • The Roles of Genetics and Gender in Autoimmune Disease

    • These genes are related to immunoglobulins, T-cell receptors, and the major histocompatibility complexes (MHC).
    • The contributions of genes outside the MHC complex remain the subject of research, in animal models of disease (Linda Wicker's extensive genetic studies of diabetes in the NOD mouse), and in patients (Brian Kotzin's linkage analysis of susceptibility to SLE).
    • HLA-DR is a MHC class II cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21.31.
    • The complex of HLA-DR and its ligand, a peptide of 9 amino acids in length or longer, constitutes a ligand for the T-cell receptor (TCR).

  • Natural Killer Cells

    • They were named "natural killers" because of the initial notion that they do not require activation in order to kill cells that are missing "self" markers of major histocompatibility complex (MHC) class 1.