Suppression of rabbit peritoneal macrophage migration by heat-labile E. coli toxin

Migration of rabbit peritoneal macrophages toward casein-serum was inhibited by preincubation of the cells with heat-labile toxin of Escherichia coli in direct relationship to the concentration of toxin in the incubation mixture. Cells preincubated with heated toxin or with toxin-antiserum migrated the same as those which had been incubated in toxin-free media. Toxin-preincubated cells had levels of cyclic AMP which were increased in direct relationship to the concentration of toxin in the preincubation mixture. Heated toxin failed to induce increased levels of cAMP in the cells at the highest concentration tested.