Campylobacter jejuni is the most common bacterial cause of diarrheal disease of humans in the United States. It has recently also been implicated as one of the most common infections to precede the development of Guillain-Barre syndrome. The study of C. jejuni pathogenesis has not yet identified many major virulence factors; in particular, almost nothing is known about the contribution of C. jejuni to disease. The broad long term goal of this proposal are to characterize the interactions of a C. jejuni toxin, called cytolethal distending toxin (CDT) with eukaryotic cells, and to determine the role of CDT in human disease. To date, CDT is the only toxin produced by C. jejuni which has actually been proven to exist. CDT blocks eukaryotic cells in the G2 phase of the cell cycle, an action unlike that of any other known bacterial toxin; and, the predicted amino acid sequence of CDT proteins share no homology with the amino acid sequences of any proteins in the database.
The specific aims of the proposal are designed to test the hypothesis that CDT is a virulence factor in C. jejuni diarrheal disease by virtue of its ability to block eukaryotic cells in the G2 phase of the cell cycle.
Under aim 1, the ability of the CDT to cause a G2 block in cultured cell line derived from intestinal epithelial cells will be tested. In addition, Dr. Pickett will test whether CDT is active against the cell lines when they are relatively undifferentiated or still proliferating.
Under aim 2, the initial interactions of CDT with HeLa cells will be characterized and experiments will be performed to determine if all or a portion of CDT enter the cells.
In aim 3, the nature of the G2 block caused by CDT will be examined in greater detail.
Under aim 4, the ability of CDT to contribute to C. jejuni diarrheal disease in a piglet model will be tested.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI041477-01
Application #
2371921
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1997-07-01
Project End
2000-06-30
Budget Start
1997-07-01
Budget End
1998-06-30
Support Year
1
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Kentucky
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
832127323
City
Lexington
State
KY
Country
United States
Zip Code
40506
Pickett, Carol L; Lee, Robert B; Eyigor, Aysegul et al. (2004) Patterns of variations in Escherichia coli strains that produce cytolethal distending toxin. Infect Immun 72:684-90
Hassane, D C; Lee, R B; Mendenhall, M D et al. (2001) Cytolethal distending toxin demonstrates genotoxic activity in a yeast model. Infect Immun 69:5752-9
Pickett, C L; Whitehouse, C A (1999) The cytolethal distending toxin family. Trends Microbiol 7:292-7
Eyigor, A; Dawson, K A; Langlois, B E et al. (1999) Cytolethal distending toxin genes in Campylobacter jejuni and Campylobacter coli isolates: detection and analysis by PCR. J Clin Microbiol 37:1646-50
Eyigor, A; Dawson, K A; Langlois, B E et al. (1999) Detection of cytolethal distending toxin activity and cdt genes in Campylobacter spp. isolated from chicken carcasses. Appl Environ Microbiol 65:1501-5