The pathogenesis of Shigella diarrhea. I. Enterotoxin production by Shigella dysenteriae 1

isolated from a patient with dysentery in Guatemala in August 1969, was found to elaborate an enterotoxin into the liquid of broth cultures. Partial purification of the enterotoxin by ultrafiltration on graded polymeric mem-branes and Sephadex gel filtration (Pharmacia Fine Chemicals, Inc., Piscataway, N. J.) suggested an ap-proximate molecular weight of 55,000-60,000. The par-tially purified toxin was heat-labile, pronase sensitive, and activated by alkaline pH, and it elicited fluid produc-tion in ligated rabbit ileal segments; it failed, however, to cause increased vascular permeability in skin. When the activities of equal weights of identically prepared Vibrio cholerae and S. dysenteriae enterotoxins were compared in the rabbit ileum the latter caused a sig-nificantly smaller volume response with increased con-centrations of potassium, chloride, and protein. The previously described neurotoxic (mouse lethal) factor was also present and eluted from Sephadex G-150 with the enterotoxin. If these biological activities prove to be possessed by a single molecular species, it is sug-gested that it be renamed Shigella enterotoxin in recog-nition of the physiologically more relevant biological action