Further antigenic determinants on HLA-A molecules.

Monoclonal antibodies detect a new polymorphic antigenic determinant shared by HLA-A2, 3, 28, 29, 30, 31 and w33. This was demonstrated by population and family studies, including an HLA-A,B recombinant family, and by lysostrip experiments. Competition experiments, measuring the binding of 125I labelled MoAbs to B lymphoblastoid cell lines coated with anti-HLA conventional alloantisera and MoAbs showed that this new epitope is spatially distant from other known epitopes of A3 molecules and from monomorphic and polymorphic determinants of A2 molecules detected by monoclonal antibodies. On the other hand, anti-HLA-A2 polyclonal alloantisera are able to inhibit binding.