Comparison of Immune Responses to the O-Specific Polysaccharide and Lipopolysaccharide of Vibrio cholerae O1 in Bangladeshi Adult Patients with Cholera

Johnson, Rebecca; Uddin, Taher; Aktar, Amena; Mohasin, M.; Alam, Mohammad Murshid; Chowdhury, Fahima; Harris, Jason B.; LaRocque, Regina C.; Bufano, Meagan Kelly; Yin, Yu; Wu-Freeman, Ying; Leung, Daniel T.; Sarracino, David; Krastins, Bryan; Charles, Richelle C.; Xu, Peng; Kòváč, Pavol; Calderwood, Stephen B.; Qadri, Firdausi; Ryan, Edward T.

doi:10.1128/cvi.00321-12

Cited by 74 publications

(126 citation statements)

References 50 publications

(79 reference statements)

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“…It has been speculated that the protective efficacy of anti-LPS antibodies is mediated through either vibriocidal activity or inhibition of adhesion to the epithelial surface (25,(96)(97)(98). We herein present an alternative mechanism by which anti-O antigen antibodies effectively block motility and thereby prevent effective colonization.…”

Section: Discussionmentioning

confidence: 91%

Lipopolysaccharide Modifications of a Cholera Vaccine Candidate Based on Outer Membrane Vesicles Reduce Endotoxicity and Reveal the Major Protective Antigen

et al. 2013

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The causative agent of the life-threatening gastrointestinal infectious disease cholera is the Gram-negative, facultative human pathogen Vibrio cholerae. We recently started to investigate the potential of outer membrane vesicles (OMVs) derived from V. cholerae as an alternative approach for a vaccine candidate against cholera and successfully demonstrated the induction of a long-lasting, high-titer, protective immune response upon immunization with OMVs using the mouse model. In this study, we present immunization data using lipopolysaccharide (LPS)-modified OMVs derived from V. cholerae, which allowed us to improve and identify the major protective antigen of the vaccine candidate. Our results indicate that reduction of endotoxicity can be achieved without diminishing the immunogenic potential of the vaccine candidate by genetic modification of lipid A. Although the protective potential of anti-LPS antibodies has been suggested many times, this is the first comprehensive study that uses defined LPS mutants to characterize the LPS-directed immune response of a cholera vaccine candidate in more detail. Our results pinpoint the O antigen to be the essential immunogenic structure and provide a protective mechanism based on inhibition of motility, which prevents a successful colonization. In a detailed analysis using defined antisera, we can demonstrate that only anti-O antigen antibodies, but not antibodies directed against the major flagellar subunit FlaA or the most abundant outer membrane protein, OmpU, are capable of effectively blocking the motility by binding to the sheathed flagellum and provide protection in a passive immunization assay.

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Section: Discussionmentioning

confidence: 91%

Lipopolysaccharide Modifications of a Cholera Vaccine Candidate Based on Outer Membrane Vesicles Reduce Endotoxicity and Reveal the Major Protective Antigen

et al. 2013

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“…Although there is mounting evidence that OPS-specific IgA antibodies are the primary contributor to mucosal immunity against V. cholerae, the mechanisms by which these antibodies interfere with V. cholerae's ability to colonize the intestinal epithelium remain poorly understood (3,9,(17)(18)(19)35). In this study, we examined the interaction between V. cholerae O395 and 2D6, a murine polymeric IgA MAb directed against the nonreducing terminal residue of Ogawa OPS (11,12,25).…”

Section: Discussionmentioning

confidence: 99%

“…Defining the relationships between epitope specificity, motility arrest, and, ultimately, protective immunity could have important implications for cholera vaccine development and assessment. For example, Johnson and colleagues recently reported that OPS and LPS serum and fecal antibody responses in convalescent individuals largely mirror each other but that vibriocidal activity was associated with OPS (35). It would be interesting to evaluate the same samples with respect to motility inhibition.…”

Section: Discussionmentioning

confidence: 99%

Rapid Effects of a Protective O-Polysaccharide-Specific Monoclonal IgA on Vibrio cholerae Agglutination, Motility, and Surface Morphology

2015

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b2D6 is a dimeric monoclonal immunoglobulin A (IgA) specific for the nonreducing terminal residue of Ogawa O-polysaccharide (OPS) of Vibrio cholerae. It was previously demonstrated that 2D6 IgA is sufficient to passively protect suckling mice from oral challenge with virulent V. cholerae O395. In this study, we sought to define the mechanism by which 2D6 IgA antibody protects the intestinal epithelium from V. cholerae infection. In a mouse ligated-ileal-loop assay, 2D6 IgA promoted V. cholerae agglutination in the intestinal lumen and limited the ability of the bacteria to associate with the epithelium, particularly within the crypt regions. In vitro fluorescence digital video microscopy analysis of antibody-treated V. cholerae in liquid medium revealed that 2D6 IgA not only induced the rapid (5-to 10-min) onset of agglutination but was an equally potent inhibitor of bacterial motility. Scanning electron microscopy showed that 2D6 IgA promoted flagellum-flagellum cross-linking, as well as flagellar entanglement with bacterial bodies, suggesting that motility arrest may be a consequence of flagellar tethering. However, monovalent 2D6 Fab fragments also inhibited V. cholerae motility, demonstrating that antibody-mediated agglutination and motility arrest are separate phenomena. While 2D6 IgA is neither bactericidal nor bacteriostatic, exposure of V. cholerae to 2D6 IgA (or Fab fragments) resulted in a 5-fold increase in surface-associated blebs, as well an onset of a wrinkled surface morphotype. We propose that the protective immunity conferred by 2D6 IgA is the result of multifactorial effects on V. cholerae, including agglutination, motility arrest, and possibly outer membrane stress. C holera is a life-threatening disease that remains endemic in many parts of the world (1-3). The etiological agent of cholera, Vibrio cholerae, is a noninvasive, Gram-negative bacterium that is acquired by humans via the fecal-oral route. Following ingestion, V. cholerae colonizes the mucosal surfaces of the small intestines, a process that is facilitated by the bacterium's single polar flagellum (4-7). Adherence to the epithelial surface requires expression of the toxin-coregulated pilus (TCP), in addition to other virulence factors (8), most notably, a potent ADP-ribosylating toxin known as cholera toxin (CT). CT disrupts chloride secretion within intestinal epithelial cells, inducing profuse water and electrolyte secretion and ultimately resulting in the hallmark "rice water diarrhea" associated with cholera. Cholera outbreaks frequently occur when water sanitation is disrupted, either following natural disasters or seasonally in areas where V. cholerae is endemic (9). The recent cholera outbreak in Haiti following the 2010 earthquake highlighted the ongoing potential of V. cholerae to cause mass causalities, as it resulted in more than half a million infected individuals and more than 7,000 deaths (10). Due to the rapid onset of symptoms and limited treatment options, control of cholera in many parts of the globe, particularly...

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“…Evaluation of immune responses to LPS might be complicated by the presence of trace amounts of contaminating membrane proteins, even in highly purified LPS preparations (16). Thus, we purified the O-specific polysaccharide-core oligosaccharide fragment (OSPc) of the outer membrane of V. cholerae O1 LPS and conjugated it to bovine serum albumin (BSA) to facilitate immunological analyses of the sugar component of LPS (17).…”

mentioning

confidence: 99%

“…Thus, we purified the O-specific polysaccharide-core oligosaccharide fragment (OSPc) of the outer membrane of V. cholerae O1 LPS and conjugated it to bovine serum albumin (BSA) to facilitate immunological analyses of the sugar component of LPS (17). We have previously shown that immune responses target the OSP moiety in this construct (16), and henceforth we refer to this antigen as OSP. Furthermore, in adults with severe cholera, we also recently demonstrated that the OSP response contributes substantially to the observed vibriocidal antibody response, and we identified plasma antibody and mucosal responses against OSP and LPS (16).…”

mentioning

confidence: 99%

Immune Responses to the O-Specific Polysaccharide Antigen in Children Who Received a Killed Oral Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh

Leung

Uddin

et al. 2013

Clin Vaccine Immunol

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g Current oral cholera vaccines induce lower levels of protective efficacy and shorter durations of protection in young children than in adults. Immunity against cholera is serogroup specific, and immune responses to Vibrio cholerae lipopolysaccharide (LPS), the antigen that mediates serogroup-specific responses, are associated with protection against disease. Despite this, responses against V. cholerae O-specific polysaccharide (OSP), a key component of the LPS responsible for specificity, have not been characterized in children. Here, we report a comparison of polysaccharide antibody responses in children from a region in Bangladesh where cholera is endemic, including infants (6 to 23 months, n ‫؍‬ 15), young children (24 to 59 months, n ‫؍‬ 14), and older children (5 to 15 years, n ‫؍‬ 23) who received two doses of a killed oral cholera vaccine 14 days apart. We found that infants and young children receiving the vaccine did not mount an IgG, IgA, or IgM antibody response to V. cholerae OSP or LPS, whereas older children showed significant responses. In comparison to the vaccinees, young children with wild-type V. cholerae O1 Ogawa infection did mount significant antibody responses against OSP and LPS. We also demonstrated that OSP responses correlated with age in vaccinees, but not in cholera patients, reflecting the ability of even young children with wild-type cholera to develop OSP responses. These differences might contribute to the lower efficacy of protection rendered by vaccination than by wild-type disease in young children and suggest that efforts to improve lipopolysaccharide-specific responses might be critical for achieving optimal cholera vaccine efficacy in this younger age group.

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Comparison of Immune Responses to the O-Specific Polysaccharide and Lipopolysaccharide of Vibrio cholerae O1 in Bangladeshi Adult Patients with Cholera

Abstract: Immunity against

Cited by 74 publications

References 50 publications

Lipopolysaccharide Modifications of a Cholera Vaccine Candidate Based on Outer Membrane Vesicles Reduce Endotoxicity and Reveal the Major Protective Antigen

Lipopolysaccharide Modifications of a Cholera Vaccine Candidate Based on Outer Membrane Vesicles Reduce Endotoxicity and Reveal the Major Protective Antigen

Rapid Effects of a Protective O-Polysaccharide-Specific Monoclonal IgA on Vibrio cholerae Agglutination, Motility, and Surface Morphology

Immune Responses to the O-Specific Polysaccharide Antigen in Children Who Received a Killed Oral Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh

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