What process is involved in the presentation of antigens from cytoplasmic pathogens on MHC class II molecules?
What process is involved in the presentation of antigens from cytoplasmic pathogens on MHC class II molecules?
Autophagy promotes MHC class II presentation of peptides from intracellular source proteins.
What antigens are presented by MHC II?
MHC class II binds antigenic peptides that are generated by proteolysis of self and non-self proteins in endosomes and lysosomes, and ‘presents’ them to antigen-specific CD4+ T cells3.
What role does MHC play in the immune system?
MHC molecules are important components of the immune system because they allow T lymphocytes to detect cells, such as macrophages, that have ingested infectious microorganisms. In uninfected healthy cells, the MHC molecule presents peptides from its own cell (self peptides), to which T cells do not normally react.
Where do MHC II molecules get loaded with antigen peptides?
Loading of a MHC class II molecule occurs by phagocytosis; extracellular proteins are endocytosed, digested in lysosomes, and the resulting epitopic peptide fragments are loaded onto MHC class II molecules prior to their migration to the cell surface.
What is MHC class 2?
MHC class II. MHC (major histocompatibility complex) class II molecules are a family of molecules normally found only on antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial cells, and B cells.
What is the role of MHC II in antigen presentation?
The MHC II molecule then travels to the surface to present the antigen to a helper T-cell. MHC II active helper T-cells which help release cytokines and other things which will help induce other cells which help to combat the pathogens outside the cells.
What is a peptide-loaded MHC class II molecule?
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 presented to antigen-specific CD4 + T cells.
Why are MHC class II complexes not expressed on the cell surface?
After MHC class II complexes are synthesized and presented on APCs they are unable to be expressed on the cell surface indefinitely, due to the internalization of the plasma membrane by the APCs. In some cells, antigens bind to recycled MHC class II molecules while they are in the early endosomes.
