Properties of Antisera to Ganglioside GM1 and Asialo GM1

Abstract

Abstract The object of this study is to prepare antisera to purified glycosphingolipids for immunocytochemical studies. Rabbits were immunized with ganglioside GM1 complexed either to methylated BSA or to a glycoprotein isolated from human erythrocytes, and to asialo GM1 complexed to the erythrocyte glycoprotein. IgG and IgM antibody fractions were separated by chromatography on Sephadex G-200 and their properties were determined by complement fixation. IgG antibodies to asialo GM1 were highly specific and exhibited little cross-reactivity with GM1 or other glycolipids, but IgM antibodies cross-reacted extensively with gangliosides GM1 and GD1b. Complement fixation of IgG anti-asialo GM1 with asialo GM1 was completely inhibited by about 15 nmoles of ganglio-N-tetraose, the carbohydrate moiety of this glycolipid. Both IgG and IgM antibodies to GM1 cross-reacted extensively with asialo GM1 and GD1b, but specific IgG antibodies to GM1 were revealed by absorption with asialo GM1. The specific and cross-reacting IgG antibodies to GM1 were inhibited by the pentaose moiety of this glycoplipid, but these antibodies were much harder to inhibit than IgG anti-asialo GM1. These results demonstrate that it is possible to prepare specific antisera to purified glycolipids with a single administration of antigen, in contrast to previous studies in which repeated injections of ganglioside mixtures were employed.