A MONOCLONAL-ANTIBODY WITH REACTIVITY TO ASIALO GM1 AND MURINE NATURAL-KILLER-CELLS

A monoclonal antibody (MAb) was prepared by the fusion of murine SP2-O myeloma cells with BALB/cByJ spleen cells that were immunized with the glycolipid asialo GM1 adsorbed to naked Salmonella. The specificity of the IgM antibody obtained was defined using various glycolipids, cell extracts and saccharides in ELISA assays and thin-layer chromatography (TLC) immunoblots. The non-reducing terminal galactose is the immunodominant residue for this antibody; however, there is undetectable reactivity to free galactose galactosylceramide or compounds with an .alpha.-linked galactose. The SH-34 antibody specifically lyses asialo GM1-expressing macrophages in the presence of complement and removes NK cells in vitro from spleen cell populations. When the specificity of the MAb was compared to that of a commercially available rabbit antiserum to asialo GM1, it was found that both cross-reacted with GM1 and asialo GM3 at high antibody concns; however, the MAb did not bind asialo GM2 while the rabbit antiserum showed substantial reactivity to this glycolipid. It is anticipated that this MAb will be useful for the study of murine and rat natural killer cells.