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.

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 ...

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.

2024年3月27日 · Both MHC I and MHC II are responsible for distinguishing between self and non-self molecules, allowing the immune system to recognize and eliminate foreign invaders. MHC Class I proteins are found on the surface of almost all nucleated cells in the body.

2025年1月9日 · Explore the distinct structures, functions, and immune roles of MHC Class I and II molecules in antigen processing and cellular expression.

2025年3月12日 · MHC class II is essential for coordinating immune responses against extracellular bacteria and parasites. Pathogens such as Mycobacterium tuberculosis manipulate MHC class II antigen processing by inhibiting phagosome maturation, preventing effective antigen presentation to CD4+ T cells.

In this Cell Science at a Glance poster article we will describe the mechanisms that lead to MHC class II trafficking to intracellular sites of foreign-antigen degradation, MHC class II binding to antigenic fragments, and the movement of MHC-class …