[Autoimmune-associated MHC class II molecules].

Abstract

The major histocompatibility complex (MHC) is a large region of highly polymorphic genes. MHC-encoded molecules bind foreign-protein antigens and form complexes that are recognized by antigen-specific T lymphocytes. Interactions between MHC-peptide complexes and T-cell receptors play a central role in the selection of the T-cell repertoire and in the elicitation of an immune response. The majority of disease associations with the MHC have been with class-II molecules. Despite the awareness of such associations, the pathophysiological role of MHC class-II molecules in conferring susceptibility to autoimmune disease is poorly understood. The recent demonstration that human class-II molecules can function as antigen-presenting molecules in vivo in a transgenic murine system paves the way to investigate the role of HLA class II molecules in regulating immune responses and disease susceptibility. These mice should be useful for studying the mechanisms by which particular human leukocyte antigen (HLA) alleles are associated with specific human-autoimmune diseases.