MHCkomplex

MHCKomplex is a term used in immunology to describe a theoretical multiprotein assembly that coordinates the steps of antigen processing, peptide loading, and surface presentation by MHC molecules. As a concept, it highlights the functional integration of processes that enable T cell recognition of pathogens and other antigens, rather than referring to a single fixed molecular entity.

In the conceptual model, MHCKomplex encompasses the core components involved in antigen presentation. This includes MHC class I and class II molecules, their chaperones and stabilizers, peptide-loading factors such as tapasin and calnexin/calreticulin, transporters associated with antigen processing (TAP1/2), and the proteasome- generated peptide repertoire. The framework also accounts for auxiliary factors that influence trafficking, stability, and quality control across endoplasmic reticulum and endosomal compartments.

Functions attributed to the MHCKomplex focus on ensuring efficient generation or acquisition of suitable peptides, secure loading onto MHC molecules, and the timely delivery of peptide-MHC complexes to the cell surface for surveillance by T cells. The concept emphasizes coordination across compartmental steps, including peptide generation, editing, assembly, and intracellular transport, as well as the regulation of surface expression levels.

Research status and usage vary; MHCKomplex is primarily a descriptive, pedagogical, or theoretical construct rather than a defined, static molecular complex. It serves as a heuristic to discuss the network of interactions that collectively govern antigen presentation. The term appears in educational materials and some theoretical discussions, with detailed, case-specific mappings remaining an area of ongoing study.

See also: Major histocompatibility complex, antigen processing and presentation, TAP, calnexin, calreticulin, tapasin.