MHC Class I Products

The antigenic agglomerate major histocompatibility complex (MHC) class I molecules present antigenic peptides to CD8-positive T cells. It is now recognized that the products of the MHC genes are antigen-presenting molecules (APM) designed for the presentation of antigen fragments (peptides) to the T-cell receptor, thus participating in the immune response (1). Recently shown is a mechanism of antigen acquisition for cross-presentation that couples the antigen presentation system of two adjacent cells and is lost in most tumours: gap-junction-mediated intercellular peptide coupling for presentation by bystander MHC class I molecules and transfer to professional antigen presenting cells for cross-priming (2). The mammalian vomeronasal organ detects social information about gender, status, and individuality. It has been shown that small peptides that serve as ligands for major histocompatibility complex (MHC) class I molecules function also as sensory stimuli for a subset of vomeronasal sensory neurons located in the basal Gao- and V2R receptor-expressing zone of the vomeronasal epithelium (3).