FITC Anti-MHC Class II antibody [M5/114]

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

MHC Class II also known as MHC II or human leukocyte antigen (HLA) class II is a protein complex with a molecular mass generally around 55 kDa. This protein is mainly expressed on the surface of antigen-presenting cells such as dendritic cells macrophages and B cells. It plays an important role in the immune system by presenting extracellular antigens to T helper cells. MHC II molecules are composed of two polypeptide chains alpha and beta which associate to form a heterodimer on the cell surface.

Biological function summary

MHC Class II molecules facilitate the immune system's recognition and response to pathogens by presenting processed antigenic peptides to CD4+ T lymphocytes. This activity involves their assembly within the endosomal-lysosomal system where they bind peptides derived from endocytosed proteins. MHC II is part of the major histocompatibility complex which includes other related molecules such as MHC Class I (HLA class I). The binding and presentation of peptides are central for the coordination of adaptive immune responses enhancing pathogen clearance and maintaining immunological memory.

Pathways

MHC Class II operates within the antigen processing and presentation pathway important for adaptive immunity. Its interaction with CD4+ T cells stimulates downstream signaling pathways leading to T cell activation and differentiation. Related proteins in the antigen presentation pathway include invariant chain (Ii) which guides MHC II to the endosome and HLA-DM which facilitates peptide loading. Together these proteins and pathways work to ensure effective immune surveillance and response.

Associated diseases and disorders

Alterations in MHC Class II expression or function are associated with autoimmune diseases such as rheumatoid arthritis and type 1 diabetes. In these conditions improper antigen presentation may lead to an inappropriate immune response against self-proteins. The involvement of MHC II in disease is often linked to specific HLA alleles which vary among individuals and influence susceptibility to autoimmune disorders. Additionally the abnormal function of connected proteins like cytokines from activated T helper cells can exacerbate these immune conditions.