Monoclonal antibodies detect polymorphic determinants shared by I-A and I-E antigens.

Binding data on inbred mouse strains and immunochemical isolation of Ia antigens with subsequent separation on non-reduced/reduced two-dimensional gels provide evidence for the cross-reactivity of monoclonal antibodies with I-A and I-E products. Thus two monoclonal antibodies were found to react with A alpha A beta as well as E alpha E beta dimers. One of these mAbs, K22 -42, reacts with the precursor form of E beta chain of B10.GD mice which is associated with the invariant chain (Ii). This indicates that the respective determinant on E beta is formed prior to association of E beta with E alpha.