Previous Article | Next Article ![]()
Infection and Immunity, May 1999, p. 2250-2257, Vol. 67, No. 5
Center of Marine Biotechnology, University of
Maryland Biotechnology Institute,1 and
Veterans Affairs Medical Center and Department of
Medicine2 and Center for Vaccine
Development,
Received 20 August 1998/Returned for modification 9 October
1998/Accepted 23 February 1999
Vibrio vulnificus is a human pathogen whose virulence
has been associated with the expression of capsular polysaccharide
(CPS). Multiple CPS types have been described; however, virulence does not appear to correlate with a particular CPS composition.
Reversible-phase variation for opaque and translucent colony
morphologies is characterized by changes in CPS expression, as
suggested by electron microscopy of cells stained nonspecifically with
ruthenium red. Isolates with opaque colony morphologies are virulent
and appear to be more thickly encapsulated than naturally occurring
translucent-phase variants, which have reduced, patchy, or absent CPS.
Previously, we have shown that the virulence of translucent-phase
variants was intermediate between opaque-phase variants and acapsular
transposon mutants, suggesting a correlation between virulence and the
amount of CPS expressed. In the present study, CPS expression of phase variants and genetically defined mutants of V. vulnificus
M06-24/O was examined by using a CPS-specific monoclonal antibody with an enzyme-linked immunosorbent assay, flow cytometry, and
immunoelectron microscopy. Semiquantitative analyses of CPS expression
correlated well among these assays, confirming that the
translucent-phase variant was intermediate in CPS expression and
retained type I CPS-specific epitopes. Cell surface expression of CPS
varied with the growth phase, increasing during logarithmic growth and
declining in stationary culture. Significantly greater CPS expression
(P = 0.026) was observed for cells grown at 30°C
than for those at 37°C. These studies confirm that phase variation
and virulence in V. vulnificus correlate with the amount of
CPS expressed and demonstrate the fluidity of bacterial polysaccharide
expression in response to environmental conditions.
0019-9567/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Differential Expression of Vibrio
vulnificus Capsular Polysaccharide
*
Corresponding author. Mailing address: Center of Marine
Biotechnology, University of Maryland Biotechnology Institute, 701 E. Pratt St., Baltimore, MD 21202. Phone: (410) 234-8827. Fax: (410)
234-8896. E-mail: wright{at}umbi.umd.edu.
Infection and Immunity, May 1999, p. 2250-2257, Vol. 67, No. 5
0019-9567/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|