Effect of Clostridium difficile enterotoxin A on ultrastructure of Chinese hamster ovary cells.
Electron microscopical immunocytochemistry and light microscopy were used to study the effect of Clostridium difficile enterotoxin A (EA) on cultured Chinese hamster ovary (CHO) cells. At 4 degrees C, immunocytochemically detected EA was randomly distributed along the plasma membrane; when cells were subsequently transferred to 37 degrees C, the EA moved into coated pits and coated vesicles within 2 min. Within 2 h of incubation at 37 degrees C with EA, the perinuclear cytoplasm of the CHO cells became highly refractile, and in 4 h, most of the cells were round; however, the majority of rounded cells excluded erythrosin B while remaining firmly attached to the culture dish plastic. When EA was removed from the cultured cells within 2 h, the cells returned to a normal morphology and formed a confluent monolayer. The nuclei of rounded cells were irregularly shaped; cytoplasmic intermediate filaments were collapsed toward the nucleus. Long bundles of parallel, 11-nm-diameter filaments appeared in the nuclei after 3 h of incubation with EA and disappeared by the fourth hour of incubation. Intoxicated cells did not undergo mitosis. Thus, EA was internalized, at least in part, by receptor-mediated endocytosis and subsequently affected the nuclei of CHO cells.
Kushnaryov
V M
VM
Department of Microbiology, Medical College of Wisconsin, Milwaukee 53226.
Sedmak
J J
JJ
D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism / Q000633:toxicity*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects; D003013:Clostridium / Q000472:pathogenicity*; D006224:Cricetinae; D004768:Enterotoxins / Q000378:metabolism / Q000633:toxicity*; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D010873:Pinocytosis; D013997:Time Factors
D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile