major histocompatibility complex

Examples of major histocompatibility complex in the following topics:

• Major Histocompatibility Complex Antigens (Self-Antigens)

  • The major histocompatibility complex (MHC) is a cell surface molecule that regulates interactions between white blood cells and other cells.
  • Major histocompatibility complex (MHC) is a cell-surface molecule encoded by a large gene family in all vertebrates.
  • A complex series of vesicles enables MHC transport from the cell, and the endoplasmic reticulum and Golgi bodies facilitate this transport during antigen processing.
  • Organ transplantation is a complex procedure that can potentially cure many chronic diseases and acute injuries.
  • MHC-I/peptide complexes enter Golgi apparatus, are glycosylated, enter secratory vesicles, fuse with the cell membrane, and externalize on the cell membrane interacting with T lymphocytes.

• 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.

• Natural Killer Cells

  • Typically, immune cells detect major histocompatibility complex (MHC) presented on cell surfaces, triggering cytokine release and lysis or apoptosis in cells that do not express MHC I or express much less of it than normal cells.
  • These receptors recognize major histocompatability complex I (MHC I), a molecule expressed on every cell to signal that the cell belongs to the body.

• 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.

• Antigen-Presenting Cells

  • The T cell receptor is restricted to recognizing antigenic peptides only when bound to appropriate molecules of the major histocompatibility complex (MHC), also known in humans as Human leukocyte antigen (HLA).
  • Dendritic cells, B cells and macrophages play a major role in the innate response, also acting as professional antigen-presenting cells (APC).
  • The host cell digests cytoplasmic proteins by a specialized enzyme complex, the proteasome, into small peptides.
  • A specialized carrier, the Transporter associated with Antigen Processing (TAP) complex moves the peptide into the endoplasmic reticulum, allowing the antigenic peptide to be coupled to an MHC Class I molecule and transported to the cell surface.
  • This MHC:antigen complex is then recognized by T cells passing through the lymph node.