Comparison of early embryonic and differentiating cell surfaces. Interaction of lectins with plasma membrane components.

1. Cells of the unincubated as well as those of primitive streak chick blastoderm, which are preparing for or are involved in morphogenetic movements, are agglutinated by wheat germ agglutinin, Ricinus communis agglutinin and concanavalin A, but not by fucose-binding protein. 2. Agglutination of these cells with soybean agglutinin occurs only after neuraminidase treatment, while that induced by concanavalin A, wheat germ and Ricinus communis agglutinins is not affected. 3. Trypsin treatment of blastoderm cells had no effect on lectin-mediated agglutination. 4. In contrast, cells derived from 10-and 12-day differentiating chick liver were agglutinated by wheat germ agglutinin only after trypsinization. 5. Mechanically dissociated embryonic liver cells, which are not agglutinated, bind more 3H-labelled wheat germ agglutinin per cell than trypsinized cells, suggesting that during differentiation there may be a spatial reorganization of wheat germ agglutinin receptors within the plasma membrane. 6. Membranes isolated from the above cell types were examined by analytical polyacrylamide gel isoelectric focusing and, in combination with affinity chromatography using wheat germ agglutinin conjugated to agarose, membrane material in the differentiating liver membrane, which binds to this lectin, was identified.