Monoclonal antibodies produced by immunization with neoglycoproteins containing galα1‐4galβ1‐4glcβ‐O and galα1‐4galβ1‐4glcnacβ‐O residues: Useful immunochemical and cytochemical reagents for blood group p antigens and a differentiation marker in burkitt lymphoma and other B‐cell malignancies

Abstract Several monoclonal antibodies (MAbs) directed to blood group P 1 (Galα1‐4Galβ1‐4GlcNAcβ‐O) and P k (Galα1‐4Galβ1‐4Glcβ‐O) determinants were produced with high efficiency by using synthetic neoglycoproteins as immunogens. The specificity of IgM and IgGI MAbs was characterized by binding to defined oligosaccharides and glycoconjugates. Antibodies that bound equally well to P 1 and P k determinants and to Galαl‐4Galβ1‐O‐derivatives were obtained, together with others that showed selective recognition of the entire trisaccharide chain. Selected antibodies were shown to be useful as reagents for detection of the blood group P antigens in glycolipid extracts of erythrocytes and on the surface of erythrocytes of different P phenotypes, demonstrated both by radioimmune assays and hemagglutination. Six IgM MAbs directed to the P k determinant bound selectively to Burkitt lymphoma cells and 2 of these antibodies (424/3D9 and 424/6A2) could be used as auxiliary reagents in immunofluorescence for diagnosis and classification of B‐cell lymphomas and leukemias using flow cytometric analysis. Eight normal individuals and 37 patients with lymphoma or leukemia were studied. Tumor cells of 2/2 patients with “Burkitt‐like” lymphoma, 1 patient with centroblastic lymphoma and 2 patients with acute leukemia were strongly stained for the P k antigen. The staining patterns for differentiation markers classified the tumor cells to a developmental stage closely related to the Burkitt cell type.