Biochemical evidence for multiple Ia molecules

Sequential immunoprecipitation and isoelectric focusing studies using anti-Ia monoclonal antibodies have shown multiple I-A and I-E Ia molecules. These studies suggest that the genes coding for Ia polypeptide chains A alpha, A beta, E beta and E alpha might have undergone further duplication and mutated. This would explain the diversity seen with Ia molecules in their ability to "present" numerous self and non-self antigens for generation of immune response.