A monoclonal antibody to human blood group B. Performance, evaluation and optimisation

A monoclonal anti-B antibody (ES-4) was obtained by fusing spleen cells from a mouse immunized with soluble human blood group B substance with mouse myeloma cell line NS-1. The antibody was shown to agglutinate optimally group B cells at pH 7.2 and 0.15 ionic strength. Increasing the ionic strength to 0.24 gave optimal reactivity over a wider pH range. Culture supernatant containing anti-B (ES-4), after pH and ionic strength adjustment could be used in unconcentrated form as a red cell typing reagent. Anti-B (ES-4) agglutinated five examples of cells of the Bweak (Bw) phenotype and one example of acquired B phenotype. In contrast three of the Bw cells and the acquired B phenotype were not agglutinated by a commercial monoclonal anti-B by a tube technique. The data suggested that the equilibrium constant of the monoclonal anti-B (ES-4) was higher than that of the commercial reagent.