Effects of Lectins on the Interaction of Diphtheria Toxin with Mammalian Cells.

摘要

The effects of concanavalin A (Con A) on diphtheria toxin-cell receptor interactions were studied. Con A had no measurable effect on toxin-receptor binding at 4 C but increased the total cell-associated toxin 4-5 fold at 37 C. An assay which distinguishes between cell surface bound and internalized toxin demonstrated that Con A reduces the percentage of internalized toxin while markedly increasing that found on the cell surface. These effects of Con A were blocked by alpha-methyl mannoside but not by colchicine. Succinyl Con A was as effective as Con A; other lectins, however, were less potent. It is concluded that Con A protects cells from diphtheria toxin by blocking its energy into the cell. (Author)