MHC (major histocompatibility complex) class II molecules are transmembrane glycoproteins expressed on the surface of professional antigen-presenting cells, such as macrophages, dendritic cells and B cells. Before their exposition on the cell surface, the MHC class II molecules react with endocytosed exogenous antigens, which are then presented to the T cells. The antigen-binding grove between MHC class II alpha and beta chain is open at both ends and is 15-24 amino acid residues long.

beta 1 domain; B-L; B-L beta chain; B-L beta minor; B-LB; BLB major; BLB1; BLB2; B-LB2; B-LB21; B-LB21 major; BLB3; Bl-Beta II protein; B-LBII; class II histocompatibility antigen, B-L beta chain; class II histocompatibility antigen, M alpha chain; D6S222E; DMA; FECA-DRB; GSP-BLB1; GSP-BLB2; HLA class II histocompatibility antigen, DM alpha chain; HLADM; HLA-DMA; major histocompatibility class II antigen B-L beta; major histocompatibility complex class II B; Major histocompatibility complex class II beta chain BLB1; Major histocompatibility complex class II beta chain BLB1, (similar to HLA class II, D beta chain); major histocompatibility complex class II beta chain BLB1, (similar to HLA class II, D beta chain); Major histocompatibility complex class II beta chain BLB2, (similar to HLA class II, D beta chain); Major histocompatibility complex class II beta chain BLB3, (similar to HLA class II, D beta chain); major histocompatibility complex, class II, DM alpha; MHC 2; MHC Class II; MHC class II antigen; MHC class II antigen beta chain; MHC class II antigen B-F minor heavy chain; MHC class II antigen DMA; MHC class II antigen DRB; MHC Class II beta 1 and 2 domains; MHC class II beta 1 domain; MHC class II beta chain; MHC class II beta chain 1; MHC class II beta chain 2; MHC class II B-L beta chain; MHC II; MHCCII; MHCFECA-DRB; really interesting new gene 6 protein; RING6; S19; uncharacterized protein LOC101747454