Absorption, elution and blocking studies with the complex antiserum ST.

Quantitative absorptions and elutions were performed with the broadly reactive serum ST. The major component of this serum is directed towards the B-locus antigens Bw35, B5, and B18, which comprise the 4c CREG. A second component contains lower titered antibodies which react with members of the 4c CREG, but also appear to detect qualitative and quantitative variations associated with B-locus specificities, B15, B17 and B8. Blocking studies indicate that these antibodies do not bind to the same sites on B8 cells as well-defined anti-B8 sera. These findings are discussed in terms of public specificities at the B-locus or a new specificity at a closely linked locus.