Studies on Lectin-induced Agglutination of Drosophila Embryonic Cell Lines

The agglutination responses of three Drosophila cell lines to concanavalin A and wheat germ agglutinin have been examined. Although the cell lines were originally derived from late embryonic stages of the Ore-R strain of Drosophila melanogaster. they show quantitative differences in lectininduced agglutination. Line 1 cells were least agglutinable with both lectins. All three cdl lines reached maximum agglutination with concanavalin A concentrations at 25 &ml. but the agglutination response to wheat germ aggiutinin was biphasic such that an initial rapid increase in agglutination with concentrations up to 25 pg/ml was followed by slower agglutination above this concentration. Cells of lines 1 and 2 from ten-day old cultures exhibited greater lectin-induced agglutination than cells from threeday old cultures. Age-dependent differences were not found for line 3 cells which gave maximum agglutination responses in both young and old cultures. Cell agglutination by concanavalin A was almost completely inhibited by pretreatment of the lectin with methyl-x+mannopyranoside, but preincubation of wheat germ agglutinin with N-acetyl+glucosamine caused only partial blockage. Lectininduced agglutination was not reversible by treatment with the monosaccharide inhibitors. These observations have been discussed with reference to the origin of the three cell lines and their cell surface properties.