[The attachment of erythroid cells to solid supports in the presence of lectins]

A comparative influence of lectins on the attachment kinetics of erythroid cells (human erythrocytes and erythroleukemia cells K562) to glass formvar has been studied. It is shown that the inhibiting effect of wheat germ agglutinin (WGA) on the adhesion to glass is the same for both types of cells under study, whereas concanavalin A (Con-A) inhibits the erythrocyte adhesion to glass only but it is ineffective for adhesion of K562 cells. Plasmatic membranes of K562 cells are free from band 3 protein contrary to the erythrocyte ones. It is concluded that the inhibition of erythrocyte adhesion by lectins results from their binding to different components of cell membranes; sialic acid residues of glycophorin (WGA) or band 3 protein (Con-A). This conclusion is confirmed by the inhibiting effect of WGA towards attachment of cells K562 to glass and the absence of such an effect of Con-A towards the same cells which do not contain this protein. The most probable form of both cell type attachment to glass is the occurrence of so-called focal contacts. The latter can be easily observed in the case of K562 cells. The intact erythrocyte attachment to formvar occurs slower than to glass. At the same time, the above lectins accelerate the erythrocyte attachment to formvar.