Optimization of Vi capsular polysaccharide production during growth of Salmonella enterica serotype Typhi Ty2 in a bioreactor

Jang, Han Byul; Yoon, Yeon Kyung; Kim, Jeong Ah; Kim, Hyo Seung; An, So Jung; Seo, Jin Ho; Cui, Changfa; Carbis, Rodney

doi:10.1016/j.jbiotec.2008.02.017

Cited by 23 publications

(12 citation statements)

References 15 publications

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“…This is probably only one of the several metabolic pathways that may have been damaged through chemical mutagenesis. Although we were unable to reach ODs higher than 9 even in fermentation conditions, Vi production per OD 600 unit was satisfactory at 12.5 g/ml/OD 600 and was substantially higher than that reported by Jang et al (11) from an optimized fermentation process of S. Typhi Ty2 that resulted in 6.1 g/ ml/OD 600 . The Vi yield obtained from a 1,000-liter fermentor of C. freundii WR7011 followed by a purification process with Ͼ50% recovery would correspond to approximately 2 million 25-g doses.…”

Section: Discussioncontrasting

confidence: 79%

Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM ₁₉₇ Conjugate as a Vaccine for Salmonella enterica Serovar Typhi

Rondini

Micoli

Lanzilao

et al. 2011

Clin Vaccine Immunol

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Typhoid fever remains a major health problem in developing countries. Young children are at high risk, and a vaccine effective for this age group is urgently needed. Purified capsular polysaccharide from Salmonella enterica serovar Typhi (Vi) is licensed as a vaccine, providing 50 to 70% protection in individuals older than 5 years. However, this vaccine is ineffective in infants. Vi conjugated to a carrier protein (i.e., an exoprotein A mutant from Pseudomonas aeruginosa [rEPA]) is highly immunogenic, provides long-term protection, and shows more than 90% protective efficacy in children 2 to 5 years old. Here, we describe an alternative glycoconjugate vaccine for S. Typhi, Vi-CRM 197 , where Vi was obtained from Citrobacter freundii WR7011 and CRM 197 , the mutant diphtheria toxin protein, was used as the carrier. We investigated the optimization of growth conditions for Vi production from C. freundii WR7011 and the immunogenicity of Vi-CRM 197 conjugates in mice. The optimal saccharide/protein ratio of the glycoconjugates was identified for the best antibody production. We also demonstrated the ability of this new vaccine to protect mice against challenge with Vi-positive Salmonella enterica serovar Typhimurium.Salmonella enterica serovar Typhi (S. Typhi) is the causative agent of typhoid fever, a systemic disease which remains a major public health problem, predominantly in children in developing countries. Estimates of the global burden of typhoid fever range from 17 to 22 million cases per year with 216,000 to 600,000 associated annual deaths (2, 9). S. Typhi expresses a virulence (Vi) capsule encoded in the viaB locus of Salmonella pathogenicity island 7 (SPI7), which allows S. Typhi to modulate host responses during infection by evading innate immune surveillance (25,26). Vi is also the main target for vaccines and a major protective antigen against typhoid fever. One of the two currently licensed typhoid fever vaccines is unconjugated Vi polysaccharide, available in more than 90 countries (41).Vi consists of repeating (␣1-4)-2-deoxy-2-N-acetyl galacturonic acid moieties and, similar to other polysaccharides consisting of repeating epitopes, is classified as thymus-independent type 2 (Ti-2) antigen (33). These types of polysaccharides provoke an immune response which is age related, with children under 2 years of age generally poor responders. Additionally, Ti-2 antigens lack affinity maturation of antibody response, generate limited immunologic memory and no booster effect, and produce predominantly immunoglobulin isotype IgM with limited class switching (1). The switch from IgM-to IgG-secreting B cells requires interaction with an activated antigen-specific CD4 ϩ T helper lymphocyte, which can be engaged by the conjugation of the polysaccharide to a carrier protein. Vi, as a Ti-2 antigen, does not generate immunological memory, and antibodies induced by Vi are not able to be boosted by repeated vaccinations (16,40).In contrast, Vi conjugated to a carrier protein provides a valid solution against those m...

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Section: Discussioncontrasting

confidence: 79%

Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM ₁₉₇ Conjugate as a Vaccine for Salmonella enterica Serovar Typhi

Rondini

Micoli

Lanzilao

et al. 2011

Clin Vaccine Immunol

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“…However, the ability to pay for the conjugate vaccine remains a major factor driving who is and who is not vaccinated. One possible way to increase the supply of affordable Vi vaccine is to optimise the production of Vi during fermentation either by modifying growth conditions [14] or by constructing S. Typhi mutants that constitutively express high levels of Vi [15]. Therefore, a better understanding of the regulation of Vi polysaccharide synthesis will not only add to our knowledge base of S. Typhi pathogenesis, but also allow us to improve Vi antigen production and therefore provide a less expensive subunit vaccine.…”

mentioning

confidence: 99%

Regulation of Vi Capsular Polysaccharide Synthesis in Salmonella enterica Serotype Typhi

Santander

Roland

Curtiss

2008

J Infect Dev Ctries

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The synthesis of Vi polysaccharide, a major virulence determinant in Salmonella enterica serotype Typhi (S. Typhi), is under the control of two regulatory systems, ompR-envZ and rscB-rscC, which respond to changes in osmolarity. Some S. Typhi isolates exhibit over-expression of Vi polysaccharide, which masks clinical detection of LPS O-antigen. This variation in Vi polysaccharide and O-antigen display (VW variation) has been observed since the initial studies of S. Typhi. We have reported that the status of the rpoS gene is responsible for this phenomenon. We review the regulatory network of the Vi polysaccharide, linking osmolarity and RpoS expression. Also, we discuss how this may impact live attenuated Salmonella vaccine development.

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“…The fermentation process has been optimized and scaled to 50 L obtaining a Vi yield of 13.1 µg/ml/OD, which is more than twice what was previously reported for fermentation of S. Typhi Ty2 [31]. Considering a 50% overall yield of the purification process, we estimate that from one single 50 L fermentation run, resulting in 700 µg/ml of crude Vi, about 17.5 g of purified Vi can be obtained [26].…”

Section: Discussionmentioning

confidence: 69%

Characterization of Citrobacter sp. line 328 as a source of Vi for a Vi-CRM197 glycoconjugate vaccine against Salmonella Typhi

Rondini

Micoli

Lanzilao

et al. 2012

J Infect Dev Ctries

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Introduction: Salmonella enterica serovar Typhi is the causative agent of typhoid fever with over 22 million cases and over 200,000 deaths reported annually. A vaccine is much needed for use in young children and the Novartis Vaccines Institute for Global Health (NVGH) is developing a conjugate vaccine which targets S. Typhi Vi capsular polysaccharide. Methodology: Here we describe a method suitable for industrial scale production of the Vi antigen based on expression by a Citrobacter line. We optimized the production of Vi by selecting a suitable Citrobacter strain (Citrobacter 328) that yields high and stable expression of Vi in chemically defined medium under industrial-scale fermentation conditions. Results: Vi-CRM 197 made using Vi from Citrobacter 328 elicited high anti-Vi antibody levels in mice and rabbits. Conclusions: Citrobacter 328 is a suitable strain for production of Vi for conjugate anti-Typhi vaccines. Being a BSL-1 organism, which grows in defined medium and stably produces high yields of Vi, it offers excellent potential for the safe production of inexpensive vaccines for populations at risk of typhoid fever.

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Optimization of Vi capsular polysaccharide production during growth of Salmonella enterica serotype Typhi Ty2 in a bioreactor

Cited by 23 publications

References 15 publications

Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM ₁₉₇ Conjugate as a Vaccine for Salmonella enterica Serovar Typhi

Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM ₁₉₇ Conjugate as a Vaccine for Salmonella enterica Serovar Typhi

Regulation of Vi Capsular Polysaccharide Synthesis in Salmonella enterica Serotype Typhi

Characterization of Citrobacter sp. line 328 as a source of Vi for a Vi-CRM197 glycoconjugate vaccine against Salmonella Typhi

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Optimization of Vi capsular polysaccharide production during growth of Salmonella enterica serotype Typhi Ty2 in a bioreactor

Cited by 23 publications

References 15 publications

Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM 197 Conjugate as a Vaccine for Salmonella enterica Serovar Typhi

Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM 197 Conjugate as a Vaccine for Salmonella enterica Serovar Typhi

Regulation of Vi Capsular Polysaccharide Synthesis in Salmonella enterica Serotype Typhi

Characterization of Citrobacter sp. line 328 as a source of Vi for a Vi-CRM197 glycoconjugate vaccine against Salmonella Typhi

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Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM ₁₉₇ Conjugate as a Vaccine for Salmonella enterica Serovar Typhi

Evaluation of the Immunogenicity and Biological Activity of the Citrobacter freundii Vi-CRM ₁₉₇ Conjugate as a Vaccine for Salmonella enterica Serovar Typhi