Detection of two distinct class II alpha:beta:Ii complexes in the Syrian hamster

Hamsters alloantisera and a monoclonal antibody originally generated against antigens controlled by the murine I-Ek subregion, which cross-reacts with hamster cell surface antigens, have been used to define two distinct Ia-like complexes in the Syrian hamster. These complexes have been named alpha 1:beta 1 and alpha 2:beta 2 and are detected by hamster alloantisera or monoclonal antibody 14-4-4, respectively. For the three strains studied, alpha 1:beta 1 appears to be polymorphic in both alpha and beta chains, while the alpha 2:beta 2 complex is nonpolymorphic, as revealed by 2-D PAGE analyses. A third nonpolymorphic glycoprotein that appears to be the hamster's equivalent of the murine invariant chain (Ii) is associated with both the alpha 1:beta 1 and alpha 2:beta 2 complexes. In addition, we report the first biochemical detection of polymorphism between the closely related CB and MHA Syrian hamster strains.