Overexpression of O‐polysaccharide chain length regulators in Gram‐negative bacteria using the Wzx‐/Wzy‐dependent pathway enhances production of defined modal length O‐polysaccharide polymers for use as haptens in glycoconjugate vaccines

Hégerlé, Nicolas; Bose, Janhabi; Ramachandran, Girish; Galen, James E.; Levine, Myron M.; Simon, Raphael; Tennant, Sharon M.

doi:10.1111/jam.13772

Cited by 21 publications

(20 citation statements)

References 42 publications

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“…38 The protein carrier is produced separately, while the conjugation step is an independent chemical process. Despite ongoing efforts toward improvements, as exemplified by a recent report on SD1 LPS production and isolation, 70 or attempts at developing cost-effective strategies for isolating preferred O-Ag vaccine haptens overcoming limitations related to the natural heterogeneity of O-Ag chain length, 71 the full process to a glycoconjugate vaccine requires multiple purification and characterization steps.…”

Section: Bioconjugates or One-pot Manufactured Vaccine Candidatesmentioning

confidence: 99%

Classical and novel strategies to develop aShigellaglycoconjugate vaccine: from concept to efficacy in human

Barel

Mulard

2019

Human Vaccines & Immunotherapeutics

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Shigella are gram-negative bacteria that cause severe diarrhea and dysentery, with a high level of antimicrobial resistance. Disease-induced protection against reinfection in Shigella -endemic areas provides convincing evidence on the feasibility of a vaccine and on the importance of Shigella lipopolysaccharides as targets of the host humoral protective immune response against disease. This article provides an overview of the original and current strategies toward the development of a Shigella glycan-protein conjugate vaccine that would cover the most commonly detected strains. Going beyond pioneering “lattice”-type polysaccharide-protein conjugates, progress, and challenges are addressed with focus on promising alternatives, which have reached phases I and II clinical trial. Glycoengineered bioconjugates and “sun”-type conjugates featuring well-defined synthetic carbohydrate antigens are discussed with insights on the molecular parameters governing the rational design of a cost-effective glycoconjugate vaccine efficacious in preventing diseases caused by Shigella in the most at risk populations, young children living in endemic areas.

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Section: Bioconjugates or One-pot Manufactured Vaccine Candidatesmentioning

confidence: 99%

Classical and novel strategies to develop aShigellaglycoconjugate vaccine: from concept to efficacy in human

Barel

Mulard

2019

Human Vaccines & Immunotherapeutics

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“…The complementation of an F. tularensis wzz1 mutant with the plasmid-encoded wzz2 gene from F. novicida led to the synthesis by F. tularensis of an OAg incorporating the number of repeat units governed by the heterologous F. novicida Wzz2 protein. The presence of distinct wzz genes controlling OAg size in gram-negative species has been reported before (58, 59), as has the use of such a strategy to increase the production of an OAg population of a defined size (60), but these genes have not been used to manipulate the molecular size of the polysaccharide, and hence the immunogenicity of a vaccine.…”

Section: Discussionmentioning

confidence: 98%

Glycoconjugate vaccine using a genetically modified O antigen induces protective antibodies toFrancisella tularensis

Stefanetti

Okan

Fink³

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Francisella tularensisis the causative agent of tularemia, a category A bioterrorism agent. The lipopolysaccharide (LPS) O antigen (OAg) ofF. tularensishas been considered for use in a glycoconjugate vaccine, but conjugate vaccines tested so far have failed to confer protection necessary against aerosolized pulmonary bacterial challenge. WhenF. tularensisOAg was purified under standard conditions, the antigen had a small molecular size [25 kDa, low molecular weight (LMW)]. Using milder extraction conditions, we found the native OAg had a larger molecular size [80 kDa, high molecular weight (HMW)], and in a mouse model of tularemia, a glycoconjugate vaccine made with the HMW polysaccharide coupled to tetanus toxoid (HMW-TT) conferred better protection against intranasal challenge than a conjugate made with the LMW polysaccharide (LMW-TT). To further investigate the role of OAg size in protection, we created anF. tularensislive vaccine strain (LVS) mutant with a significantly increased OAg size [220 kDa, very high molecular weight (VHMW)] by expressingin F. tularensisa heterologous chain-length regulator gene (wzz) from the related speciesFrancisella novicida. Immunization with VHMW-TT provided markedly increased protection over that obtained with TT glycoconjugates made using smaller OAgs. We found that protective antibodies recognize a length-dependent epitope better expressed on HMW and VHMW antigens, which bind with higher affinity to the organism.

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“…S . Typhimurium COPS and FliC were purified as described (13) from CVD 1925wzzB and isolate D65 to isolate I77, an attenuated derivative of the Malian blood isolate D65, which has deletions in fljB and fliD (lacks expression of phase II flagella and secretes phase I flagellar subunits), and overexpresses wzzB , ensuring the production of uniformly long-chain OPS (13, 17). Endotoxin removal was confirmed by endpoint limulus amebocyte lysate assay (Endosafe -PTS, Charles River, MA).…”

Section: Methodsmentioning

confidence: 99%

Maternal Antibodies Elicited by Immunization With an O- Polysaccharide Glycoconjugate Vaccine Protect Infant Mice Against Lethal Salmonella Typhimurium Infection

et al. 2019

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Non-typhoidal Salmonella (NTS) are a leading cause of pediatric invasive bacterial infections in sub-Saharan Africa with high associated case fatality rates in children under 5 years old. We have developed glycoconjugate vaccines consisting of the lipid A-removed surface polysaccharide of NTS, core and O-polysaccharide (COPS), and the flagellar monomer protein (FliC) from the homologous serovar as the carrier. We previously established that COPS:FliC was immunogenic and protective in mice immunized as adults or infants; however, the brief period of murine infancy precluded the evaluation of protection against invasive NTS (iNTS) disease in early life. In the present study, we used a mouse model of maternal immunization to investigate transmission of S. Typhimurium COPS:FliC-induced maternal antibodies and protection against lethal iNTS challenge in infant mice. We found that vaccinated dams developed high levels of COPS- and FliC-specific IgG, which were transferred to their offspring. Sera from both vaccinated mothers and their litters mediated complement-dependent bactericidal activity in-vitro. Passively immunized 2-week old infant mice born to vaccinated mothers were fully protected from challenge with an S. Typhimurium blood isolate from sub-Saharan Africa. The pre-clinical findings reported herein demonstrate that anti-COPS:FliC antibodies induced by vaccination are sufficient for protection of murine infants against experimental S. Typhimurium infection. By underscoring the protective role of antibody, our results suggest that maintaining an adequate titer of protective anti-Salmonella antibodies during early life, either through pediatric or maternal COPS:FliC vaccination, may reduce iNTS disease in young children in sub-Saharan Africa.

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Overexpression of O‐polysaccharide chain length regulators in Gram‐negative bacteria using the Wzx‐/Wzy‐dependent pathway enhances production of defined modal length O‐polysaccharide polymers for use as haptens in glycoconjugate vaccines

Abstract: The methods presented herein represent a cost-effective and improved strategy for isolating preferred OPS vaccine haptens, and could facilitate the further use of O-polysaccharides in glycoconjugate vaccine development.

Cited by 21 publications

References 42 publications

Classical and novel strategies to develop aShigellaglycoconjugate vaccine: from concept to efficacy in human

Classical and novel strategies to develop aShigellaglycoconjugate vaccine: from concept to efficacy in human

Glycoconjugate vaccine using a genetically modified O antigen induces protective antibodies toFrancisella tularensis

Maternal Antibodies Elicited by Immunization With an O- Polysaccharide Glycoconjugate Vaccine Protect Infant Mice Against Lethal Salmonella Typhimurium Infection

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