Interactions of embryonic and fetal neural retina cells with carbohydrate-binding phytoagglutinins: Cell surface changes with differentiation

Abstract

Agglutination of embryonic and fetal chick neural retina cells by concanavalin A (Con A), wheat germ agglutinin (WGA) and castor bean agglutinin (ricin) was examined to determine the availability of carbohydrate-containing receptor sites for these lectins on the cell surface at different stages of development. Cells in suspensions obtained from retina tissue by treatment with EGTA and by trypsinization were compared. Consistent patterns of differences in the reaction of retina cells with these lectins were found, reflecting the developmental state of the cells, procedure of preparation of cell suspension, and kind of lectin. Ricin agglutinated to the same degree cells of all developmental ages, obtained by EGTA treatment or by trypsinization, suggesting abundance of receptor sites for this lectin throughout the surface of these cells at all developmental stages examined. WGA agglutinated only trypsinized cells, which suggests that WGA receptors on retina cells are masked at all developmental stages tested by a trypsin-sensitive material. Con A readily agglutinated EGTA-separated retina cells from earlier embryos, but was less effective or ineffective on EGTA-separated cells from fetal stages; the latter could be made to agglutinate with Con A by treatment with trypsin, which shows that, as the retina differentiates and matures Con A receptors on its cells become masked with a trypsin-sensitive material. The results provide definitive evidence of changes in the surface of embryonic cells correlated with differentiation and maturation.