Cell surface receptors for wheat germ agglutinin and limulin in baby hamster kidney cells and ricin resistant variants.

The cell surface glycoconjugates of Baby Hamster Kidney cells and of four ricin resistant variants were investigated by the use of 125I-substituted ricin (Ricinus communis toxin) which binds galactose residues, and by the use of fluorescein labelled lectins which bind N-acetylneuraminic acid and/or N-acetylglucosamine: Limulin (Limulus polyphemus agglutinin), wheat germ agglutinin (Triticum vulgare agglutinin) and succinylated wheat germ agglutinin. Striking differences in the number of lectin and/or ricin receptors were found between the cell surface of wild type cells and that of ricin resistant variants. The results are discussed on the basis of the main glycopeptide structure, and of the specificity of the sugar binding proteins used. The ricin resistance of variant cells is concomitant to modifications of the concentration of certain glycoconjugate structures which are accessible to the sugar binding proteins. Depending on the variants, N-asparaginyl glycopeptide types and/or O-glycosidic glycopeptide types are affected.