PR:000001821 MHC class II histocompatibility antigen beta chain MHCcIIbeta has_part Pfam:PF07654 Immunoglobulin C1-set domain 20090326 PRO:CNA PR:000001821 MHC class II histocompatibility antigen beta chain MHCcIIbeta has_part Pfam:PF00969 Class II histocompatibility antigen, beta domain 20090326 PRO:CNA