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Vibrio cholerae hemagglutinin/protease inactivates CTXphi
1Division of Geographic Medicine, Tupper Research Institute, New England Medical Center, Boston, Massachusetts 02111, USA.
Infection and Immunity
|August 26, 1998
Summary
Vibrio cholerae produces a factor that destroys CTXphi phage infectivity during later growth stages. This CTXphi-destroying factor (CDF) is identified as the secreted hemagglutinin/protease (HA/P), potentially preventing reinfection.
Area of Science:
- Microbiology
- Virology
- Molecular Biology
Background:
- Pathogenic Vibrio cholerae are lysogens of CTXphi phage, which encodes cholera toxin.
- CTXphi infection is crucial for V. cholerae pathogenesis.
Purpose of the Study:
- To investigate the mechanism behind the loss of CTXphi infectivity in late-stage V. cholerae cultures.
- To identify the factor responsible for destroying CTXphi infectivity.
Main Methods:
- Monitoring CTXphi titers in V. cholerae culture supernatants across growth phases.
- Assessing CTXphi infectivity destruction by stationary-phase supernatants.
- Gene disruption and complementation experiments for the hemagglutinin/protease (HA/P) gene.
- Purification and characterization of the CTXphi-destroying factor (CDF).
Main Results:
- CTXphi titers decreased significantly in stationary-phase V. cholerae cultures.
- Stationary-phase supernatants destroyed CTXphi infectivity, mediated by CDF.
- CDF activity was absent in a V. cholerae strain with a disrupted HA/P gene.
- Purified CDF contained a 45-kDa polypeptide identical to HA/P.
- CDF levels correlated with secreted HA/P in various V. cholerae strains.
Conclusions:
- Secreted hemagglutinin/protease (HA/P) from V. cholerae acts as CTXphi-destroying factor (CDF).
- HA/P production may prevent CTXphi reinfection in natural and host environments.
- This finding offers insights into V. cholerae lysogeny regulation and phage dynamics.