The nascent MHC class II protein in the rough ER has its peptide-binding cleft blocked by the invariant chain (Ii; a trimer) to prevent it from binding cellular peptides or peptides from the endogenous pathway (such as those that would be loaded onto class I MHC).

2022年1月5日 · MHC class I molecules consist of one membrane-spanning α chain produced by MHC genes, and one β chain produced by the β2-microglobulin gene. MHC class II molecules consist of two membrane-spanning chains, α and β both produced by MHC genes.

MHC class II presents peptide fragments that are generally larger than those presented by MHC class I, because the peptide-binding groove of MHC class II is open, allowing peptides to extend out of this site.

2013年7月18日 · Expression of HLA class II molecules is regulated at the transcriptional level by a complex process involving highly conserved sequences, which recruit specific binding factors and generate the HLA class II enhanceosome.

2022年5月22日 · Class II MHC Molecule. Class II MHC molecules are heterodimers and characterized by two non-covalently connected polypeptide chains. The chains are termed a heavy chain (α, 30kDa) and light chain (β, 26kDa).

2023年8月31日 · MHC-I presents epitopes to T8-lymphocytes; MHC-II presents epitopes to T4-lymphocytes. MHC-I molecules are designed to enable the body to recognize infected cells and tumor cells and destroy them with cytotoxic T-lymphocytes or CTLs.

Antigenic peptide-loaded MHC class II molecules (peptide–MHC class II) are constitutively expressed on the surface of professional antigen-presenting cells (APCs), including dendritic cells, B cells, macrophages and thymic epithelial cells, and are ...