title: Cell cycle arrest & apoptosis of epithelial cell line by cytolethal distending toxin positive Campylobacter jejuni.
abstract: OBJECTIVE
  Campylobacter jejuni is the leading cause of gastroenteritis worldwide; cytolethal distending toxin (CDT) being an important virulence determinant. As its role in pathogenesis remains unclear, this study aims to investigate cell cycle arrest and apoptosis by CDT (+ve) and CDT (-ve) C. jejuni isolates on HeLa cells.
  
  
  METHODS
  Culture supernatants and lysates from 10 C. jejuni isolates [CDT (+ve) and CDT (-ve), five each] were incubated with HeLa cells. CDT activity on HeLa cells was confirmed by cell distension, cell cycle arrest by flowcytometry, and apoptosis by DNA fragmentation and flowcytometry.
  
  
  RESULTS
  Culture supernatant and lysate of only CDT (+ve) C. jejuni isolates produced cell distension. For CDT (+ve) and CDT (-ve) isolates, the cells at G2/M phase after 24, 48 and 72 h were 25.8 +/- 3.79 per cent and 11.2 +/- 0.58 per cent, 72.9 +/- 2.44 and 14.3 +/- 1.88 per cent, 93.5 +/- 0.54 per cent and 18.0 +/- 1.80 per cent respectively (P<0.001). All CDT (+ve) isolates induced DNA fragmentation. Apoptosis induced by CDT (+ve) C. jejuni was significantly greater than CDT (-ve) (26.3 +/- 3.49 % vs. 10.4 +/- 1.01% at 24 h, 43.9 +/- 2.40% vs. 17.6 +/- 0.88% at 48 h, 68.4 +/- 1.61% vs. 28.4 +/- 1.62% at 72 h); (P<0.001).
  
  
  CONCLUSIONS
  The present study shows that CDT (+ve) C. jejuni contributes to the pathogenesis through epithelial cell G2/M phase arrest and apoptosis.
authors.affiliation: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
authors.forename: Deepika
authors.initials: D
authors.lastname: Jain
authors.forename: K N
authors.initials: KN
authors.lastname: Prasad
authors.forename: Sushmita
authors.initials: S
authors.lastname: Sinha
authors.forename: A L
authors.initials: AL
authors.lastname: Vishwakarma
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001427:Bacterial Toxins / Q000633:toxicity*; D016123:Campylobacter jejuni / Q000737:chemistry* / Q000235:genetics; D002453:Cell Cycle / Q000187:drug effects*; D053938:DNA Fragmentation / Q000187:drug effects; D017931:DNA Primers / Q000235:genetics; D004847:Epithelial Cells / Q000187:drug effects*; D005434:Flow Cytometry; D005759:Gastroenteritis / Q000382:microbiology*; D006367:HeLa Cells; D006801:Humans
chemical_list: D001427:Bacterial Toxins; D017931:DNA Primers