New Roles for MHC Class I Immune Molecules in the Healthy and Diseased Nervous System

Proteins of the major histocompatibility complex class I (MHC class I) are best known for their central role in the immune response. However, accumulating evidence shows that MHC class I proteins also have nonimmune roles in the healthy nervous system. MHC class I is expressed by developing and adult neurons, and is required for the proper establishment, function and modification of synaptic connections. The newly discovered, critical functions of MHC class I in the healthy nervous systemsuggest that MHCclass I coulddirectly link the immune response to changes in brain structure and function in diverse neurological disorders.