Outer Membrane Protein OmpW Is the Receptor for Typing Phage VP5 in the Vibrio cholerae O1 El Tor Biotype

ABSTRACT The outer membrane protein OmpU of Vibrio cholerae O1 strain 86B3 was characterized with reference to colonization of the intestine by the organism. The purified OmpU exhibited a pI of 3.6. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it migrated to 38, 32, and 110 kDa when the sample was heated at 100°C for 2 min, 50°C for 15 min, and room temperature for 30 min, respectively. The purified OmpU was not hemagglutinative. Anti-OmpU serum did not agglutinate strain 86B3 or other V. cholerae organisms. OmpU adhered to the brush border of the rabbit small intestine; adhesion of the organisms to the intestine treated in advance with OmpU was not inhibited. Treating the organisms in advance with anti-OmpU Fab did not inhibit adhesion to the intestine. These results obtained in vitro suggest that OmpU is not involved in the adhesion of V. cholerae to the intestinal epithelium.

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Production and characterisation of monoclonal antibodies to outer-membrane-protein antigens of Vibrio cholerae O1

Journal of Medical Microbiology ◽

10.1099/00222615-34-3-167 ◽

1991 ◽

Vol 34 (3) ◽

pp. 167-173 ◽

Cited By ~ 2

Author(s):

S. Kabir

Keyword(s):

Monoclonal Antibodies ◽

Membrane Protein ◽

Outer Membrane ◽

Vibrio Cholerae ◽

Outer Membrane Protein ◽

Protein Antigens ◽

Vibrio Cholerae O1

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Structural features, properties and regulation of the outer-membrane protein W (OmpW) of Vibrio cholerae

Microbiology ◽

10.1099/mic.0.27995-0 ◽

2005 ◽

Vol 151 (9) ◽

pp. 2975-2986 ◽

Cited By ~ 65

Author(s):

Bisweswar Nandi ◽

Ranjan K. Nandy ◽

Amit Sarkar ◽

Asoke C. Ghose

Keyword(s):

Membrane Protein ◽

Recombinant Protein ◽

Outer Membrane ◽

Vibrio Cholerae ◽

Outer Membrane Protein ◽

Secondary Structure Prediction ◽

Sequence Data ◽

Insertion Mutagenesis ◽

Sds Page

The outer-membrane protein OmpW of Vibrio cholerae was studied with respect to its structure, functional properties and regulation of expression. On SDS-PAGE, the membrane-associated form of OmpW protein (solubilized by either 0·1 % or 2 % SDS at 25 °C) migrated as a monomer of 19 kDa that changed to 21 kDa on boiling. The protein was hyperexpressed in Escherichia coli in the histidine-tagged form and the purified His6-OmpW (heated or unheated) migrated as a 23 kDa protein on SDS-PAGE. Circular dichroism and Fourier-transform infrared spectroscopic analyses of the recombinant protein showed the presence of β-structures (∼40 %) with minor amounts (8–15 %) of α-helix. These results were consistent with those obtained by computational analysis of the sequence data of the protein using the secondary structure prediction program Jnet. The recombinant protein did not exhibit any porin-like property in a liposome-swelling assay. An antiserum to the purified protein induced a moderate level (66·6 % and 33·3 % at 1 : 50 and 1 : 100 dilutions, respectively) of passive protection against live vibrio challenge in a suckling mouse model. OmpW-deficient mutants of V. cholerae strains were generated by insertion mutagenesis. In a competitive assay in mice, the intestinal colonization activities of these mutants were found to be either only marginally diminished (for O1 strains) or 10-fold less (for an O139 strain) as compared to those of the corresponding wild-type strains. The OmpW protein was expressed in vivo as well as in vitro in liquid culture medium devoid of glucose. Interestingly, the glucose-dependent regulation of OmpW expression was less prominent in a ToxR− mutant of V. cholerae. Further, the expression of OmpW protein was found to be dependent on in vitro cultural conditions such as temperature, salinity, and availability of nutrients or oxygen. These results suggest that the modulation of OmpW expression by environmental factors may be linked to the adaptive response of the organism under stress conditions.

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Naturally Occurring IgG Antibodies Provide Innate Protection against Vibrio cholerae Bacteremia by Recognition of the Outer Membrane Protein U

Journal of Innate Immunity ◽

10.1159/000443646 ◽

2016 ◽

Vol 8 (3) ◽

pp. 269-283 ◽

Cited By ~ 17

Author(s):

Kyaw Min Aung ◽

Annika E. Sjöström ◽

Ulrich von Pawel-Rammingen ◽

Kristian Riesbeck ◽

Bernt Eric Uhlin ◽

...

Keyword(s):

Membrane Protein ◽

Outer Membrane ◽

Vibrio Cholerae ◽

Outer Membrane Protein ◽

Membrane Vesicles ◽

Outer Membrane Vesicles ◽

Immune Defense ◽

Dependent Manner ◽

Naturally Occurring ◽

Serum Killing

Cholera epidemics are caused by Vibrio cholerae serogroups O1 and O139, whereas strains collectively known as non-O1/non-O139 V. cholerae are found in cases of extraintestinal infections and bacteremia. The mechanisms and factors influencing the occurrence of bacteremia and survival of V. cholerae in normal human serum have remained unclear. We found that naturally occurring IgG recognizing V. cholerae outer membrane protein U (OmpU) mediates a serum-killing effect in a complement C1q-dependent manner. Moreover, outer membrane vesicles (OMVs) containing OmpU caused enhanced survival of highly serum-sensitive classical V. cholerae in a dose-dependent manner. OMVs from wild-type and ompU mutant V. cholerae thereby provided a novel means to verify by extracellular transcomplementation the involvement of OmpU. Our data conclusively indicate that loss, or reduced expression, of OmpU imparts resistance to V. cholerae towards serum killing. We propose that the difference in OmpU protein levels is a plausible reason for differences in serum resistance and the ability to cause bacteremia observed among V. cholerae biotypes. Our findings provide a new perspective on how naturally occurring antibodies, perhaps induced by members of the microbiome, may play a role in the recognition of pathogens and the provocation of innate immune defense against bacteremia.

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