title: Cytotoxins in non-enterotoxigenic strains of Escherichia coli isolated from feces of diarrheic calves.
abstract: We have examined the cytotoxic responses produced in HeLa and Vero cell cultures by sonicates from 15 non-enterotoxigenic (STa-, LT-) strains of E. coli, highly lethal for mice parenterally LD50 less than 3 X 10(7) CFU), which had been isolated from feces of diarrheic calves. Three types of cytotoxic responses were observed. Type 1 (five strains) consisted of enlargement, rounding and polynucleation of HeLa cells, an effect previously reported with cytotoxic necrotizing factor (CNF) in E. coli from infant and piglet enteritis. Type 2 toxicity (three strains and the control Vir strain S5) was also characterized by enlargement and polynucleation of HeLa cells, but in contrast to Type 2 effect, cells were elongated. Sonicates from the latter strains were lethal for chickens, producing the lesions previously described with Vir strains. Type 3 toxicity (two strains and the control VT strain H19), produced an extensive destruction of both Vero and HeLa cell cultures. Cytotoxic effects were completely abolished upon heating for 1 h at 60 degrees C for Type 1 and 2 extracts and at 80 degrees C for Type 3 extracts. Seroneutralization assays showed that cytotoxins of the same type were closely related antigenically. In addition, a slight cross-neutralization was observed between Type 1 (CNF) and Type 2 (Vir) toxins.
authors.affiliation: Institut National de la Recherche Agronomique, Station de Pathologie de la Reproduction, Nouzilly, France.
authors.forename: J
authors.initials: J
authors.lastname: De Rycke
authors.forename: J F
authors.initials: JF
authors.lastname: Guillot
authors.forename: R
authors.initials: R
authors.lastname: Boivin
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D002470:Cell Survival; D002645:Chickens; D003603:Cytotoxins / Q000633:toxicity*; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004926:Escherichia coli; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins; D005243:Feces / Q000382:microbiology; D005260:Female; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009500:Neutralization Tests; D014709:Vero Cells
chemical_list: D001427:Bacterial Toxins; D003603:Cytotoxins; D029968:Escherichia coli Proteins; C086995:cytotoxic necrotizing factor type 2; C060296:cytotoxic necrotizing factor type 1