Influence of lectins on the binding of 125I-labeled EGF to human fibroblasts.

Lectins that interact with mannose (concanavalin A), galactose (ricin, abrin), or N-acetylglucosamine (wheat germ agglutinin) block ¹²⁵I-labeled EGF binding to the surface of cultured human fibroblasts at 37° or 5°. Lectins specific for fucose or N-acetylgalactosamine, soybean agglutinin or gorse lectin, respectively, do not interfere with growth factor binding. The inhibition of ¹²⁵I-labeled EGF binding by concanavalin A at 37° or 5° could be reversed rapidly by the addition of α-methyl mannoside. The results suggest that the fibroblast membrane receptor for EGF is, or is closely associated with, a glycoprotein or glycolipid that contains mannose, galactose and N-acetylglucosamine residues.