2022年4月13日 · Compartmentalization of proteolysis and the distinct intracellular distributions of MHC molecules are the primary drivers of antigen processing and presentation.

Cells use a variety of mechanisms to acquire protein antigens, from translation in the cytosol to variations on the theme of endocytosis, and to degrade them once acquired. In this review we highlight the aspects of MHC-I and MHC-II biosynthesis and assembly that have evolved to intersect these pathways and sample the peptides that are produced.

The difference is that the peptides originate from different sources – endogenous, or intracellular, for MHC class I; and exogenous, or extracellular for MHC class II. There is also so called cross-presentation in which exogenous antigens can be presented by MHC class I molecules. Endogenous antigens can also be presented by MHC class II when ...

1999年12月21日 · Here, we provide evidence for an additional antigen-processing pathway in immature dendritic cells (DC). Immature DC express at the cell surface empty or peptide-receptive class II MHC molecules, as well as H-2M or HLA-DM. Secreted DC proteases act extracellularly to process intact proteins into antigenic peptides.

1999年12月21日 · Here, we provide evidence for an additional antigen-processing pathway in immature dendritic cells (DC). Immature DC express at the cell surface empty or peptide-receptive class II MHC molecules, as well as H-2M or HLA-DM. Secreted DC proteases act extracellularly to process intact proteins into antigenic peptides.

2019年1月1日 · Extracellular antigens are presented by APCs following internalization, processing and loading of the resulting peptides onto Major Histocompatibility Complex (MHC) class II molecules, which are exposed on the plasma membrane to activate CD4 + T cells. This process is part of the endocytic pathway of APCs and has been characterized extensively.

2014年1月1日 · These four processing pathways allow antigenic peptides to be presented efficiently to both CD4 + and CD8 + T cells, so that both subsets will respond to extracellular and intracellular entities as required.

This process involves two distinct pathways for processing of antigens from an organism's own (self) proteins or intracellular pathogens (e.g. viruses), or from phagocytosed pathogens (e.g. bacteria); subsequent presentation of these antigens on class I or class II major histocompatibility complex (MHC) molecules is dependent on which pathway ...

Peptides derived from intracellular anti-gens are generally presented to CD8 + cells T byMHC class I molecules, which are expressed on virtually al cells, while extracellular antigen-derived are presented to CD4 + cells T by the MHC class II molecules found …

Here, we provide evidence for an additional antigen-processing pathway in immature dendritic cells (DC). Immature DC express at the cell surface empty or peptide-receptive class II MHC molecules, as well as H-2M or HLA-DM. Secreted DC proteases act extracel-lularly to process intact proteins into antigenic peptides.