MHC Class II
MHC (major histocompatibility complex) Class II molecules are found only on antigen-presenting cells and lymphocytes.
The antigens presented by class II peptides are derived from extracellular proteins (not cytosolic as in class I); hence, the MHC class II-dependent pathway of antigen presentation is called the endocytic or exogenous pathway.
Loading of MHC class II occurs by phagocytosis; extracellular proteins are endocytosed, ingested in lysosomes, and created by the class II MHC molecule prior to the molecule's migration to the cellular membrane.
Read more about MHC Class II: Structure, Reaction To Bacteria, Synthesis, Genes
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