Immunochemical studies of organ and tumor lipids XVIII. Cytolipin R determinants in the rat erythrocyte membrane

Abstract

Rabbit antisera to rat lymphosarcoma contain antibodies that agglutinate trypsinized rat erythrocytes. These reactions can be specifically inhibited by cytolipin R, a ceramide tetrasaccharide isolated from rat lymphosarcoma. The agglutinin in the rabbit antisera can be absorbed with untreated erythrocytes, showing that cytolipin R determinants are present in the intact rat erythrocyte membrane. Untreated erythrocytes are able to react with antibody, but presumably the number of cytolipin R determinants necessary for agglutination becomes available only after treatment with trypsin. The anti-cytolipin R antibodies in anti-rat lymphosarcoma sera that cause hemagglutination and those that fix complement with this hapten are different, since the agglutinin can be absorbed completely without appreciable decrease in complement-fixing antibody.

Recognition by a natural cytotoxic antibody of lactoneotetraglycosyl ceramide as an antigenic molecule in a syngeneic rat fibrosarcoma

“…A, B, C and F are CMH, CDH, amino CTH and CPH, respectively. Except for the unknown Fr.G, all the GSLs in these tumor cells are synthesized by a lacto-series pathway and none are synthesized by the globo-series pathway that has been considered the major pathway of GSL synthesis in normal rat tissues (Siddiqui et al, 1972;Graf and Rapport, 1970). The metabolic shift from the globo-to the lacto-series pathway must have occurred in these tumor cells as it does in embryogenesis and carcinogenesis (Gooi et a/.…”