Cross-blocking studies with monoclonal antibodies against I-A molecules of haplotypes b, d and k.

For assessment of the distribution of allodeterminants on I-A molecules, binding inhibition studies were performed with monoclonal anti-I-A antibodies (mAb) in which pairs of labeled and unlabeled mAb were tested for cross-blocking on spleen cells of H-2 haplotypes b, d and k. The data suggest that allodeterminants are randomly distributed on the surface of the I-A molecule. Comparison of mAb with cross-reactivity for b, d or k haplotypes indicates that the allelic forms of determinants are located in analogous positions on different I-A antigens.