Front Immunol. 2015 Sep 09;6:464. doi: 10.3389/fimmu.2015.00464. eCollection 2015.
Frontiers in immunology
Carol S K Leung
PMID: 26441969 PMCID: PMC4563256 DOI: 10.3389/fimmu.2015.00464
Antigenic peptides presented by major histocompatibility complex (MHC) class II molecules are generally derived from exogenous proteins acquired by antigen presenting cells. However, in some circumstances, MHC class II molecules can present intracellular proteins expressed within the antigen-presenting cells. There are several described pathways by which endogenous antigens are degraded and gain access to MHC class II molecules. These include autophagy and other non-autophagic pathways; the latter category includes the MHC class I-like pathways, heat shock protein 90-mediated pathways, and internalization from the plasma membrane. This review will summarize and discuss the non-autophagic pathways.
Keywords: MHC class II molecules; antigen presentation; endogenous presentation; intracellular antigens; non-classical pathways