[Target epitopes of monoclonal antibodies against ABH structures]

Comparing the reactivities of murine and human monoclonal antibodies directed against the antigens of A, B, and H blood groups by using different techniques (agglutination, inhibition by synthetic oligosaccharides and salivary antigens, tissue immunofluorescence, the use of an anti-idiotype antibody) enabled us to show a high heterogeneity of anti-A, anti-AB antibodies and, to some extend, anti-B and anti-H antibodies. Despite this diversity, the determination of the antibody specificity thanks to synthetic antigens made it possible to distinguish several groups of anti-A, B, AB, and H antibodies and to establish a classification that takes also their reactivity towards salivary and tissue antigens into account. On the contrary, few correlations were found between these tests and the ability of antibodies to agglutinate red blood cells of the different ABO-system variants.