An electron microscopic cytochemical study on concanavalin A binding sites and their mobility in normal and cystic fibrosis fibroblasts in vitro.

Concanavalin A (Con A) binding sites were visualized ultrastructurally in the cultured 
fibroblasts from cystic fibrosis patients, obligatory heterozygotes, and normal individuals by 
peroxidase labeling technique. Con A binding sites were localized as a 
continuous layer on the external side of the plasma membrane in 
fixed fibroblasts of the three genotypes. In living cells, Con A 
induces both lateral and vertical movements of binding sites as expressed 
by cap formation and internalization of the plasma membrane. Fibroblasts of 
the three genotypes responded similarly to Con A treatment and failed 
to show significant detectable differences. 