Analytical development to support manufacturing of a sustainable vaccine against Invasive Nontyphoidal Salmonellosis

GVGH is developing a candidate trivalent Salmonella vaccine to fight invasive nontyphoidal Salmonellosis (iNTS) and typhoid fever, especially aimed for sub-Saharan Africa to impact disease burden and to reduce anti-microbial resistance spread. This trivalent vaccine may be the only viable option for a sustainable iNTS vaccine in sub-Saharan Africa over the separate administration of Typhoid Conjugate Vaccines (TCV) and a vaccine against iNTS. GVGH generated the iNTS-TCV formulation by combining the GMMA technology for the iNTS components, S. Typhimurium (STm) and S. Enteritidis (SEn) GMMA adsorbed on Alhydrogel, and the Vi-CRM197 glycoconjugate, originally developed by GVGH and recently WHO prequalified as TCV TYPHIBEV by Biological E Ltd (Hyderabad, India). A set of analytical methods to support the vaccine lot release and characterization have been developed by GVGH. In particular, to quantify the key active ingredients of iNTS components a competitive ELISA-based method (FAcE, Formulated Alhydrogel competitive ELISA assay) has been setup and characterized in terms of specificity, accuracy and precision. Vi component is instead characterized by means of HPAEC-PAD method, able to specifically identify and quantify the total polysaccharide in the final drug product. With regard to safety assessment, a Monocyte Activation Test (MAT) has been developed as to monitor the intrinsic pyrogenicity of GMMA-based vaccines and applied as surveillance test for the Phase 1 clinical lot, with the plan to set release criteria based on clinical experience. In vivo potency assay has been set to characterize the immunogenicity of vaccine lots in comparison to freshly formulated material at the time of release and during real-time stability. A significant antibody response to each of the active ingredients of the trivalent vaccine is raised in mice and assessed by Parallel Line Assay. Overall, the applied analytical panel and the results support the development of an iNTS-TCV vaccine as a viable option for a sustainable iNTS vaccine in sub-Saharan Africa

La protección social en la Argentina

Fil: Cappelletti, Beatriz.Fil: Iacona, Juan.Fil: Lanari, María Estela. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Matheu, Pedro.Fil: Peralta, Marcel.Fil: Pucciarello, Mariana.Fil: Roca, Emilia.Fil: Slavin, Eleonora. Universidad Nacional de Mar del Plata. Facultad de Derecho; Argentina.Fil: Villarroel, Amalia

Recombinant Clostridium difficile Toxin Fragments as Carrier Protein for PSII Surface Polysaccharide Preserve Their Neutralizing Activity

Clostridium difficile is a Gram-positive bacterium and is the most commonly diagnosed cause of hospital-associated and antimicrobial-associated diarrhea. Despite the emergence of epidemic C. difficile strains having led to an increase in the incidence of the disease, a vaccine against this pathogen is not currently available. C. difficile strains produce two main toxins (TcdA and TcdB) and express three highly complex cell-surface polysaccharides (PSI, PSII and PSIII). PSII is the more abundantly expressed by most C. difficile ribotypes offering the opportunity of the development of a carbohydrate-based vaccine. In this paper, we evaluate the efficacy, in naive mice model, of PSII glycoconjugates where recombinant toxins A and B fragments (TcdA_B2 and TcdB_GT respectively) have been used as carriers. Both glycoconjugates elicited IgG titers anti-PSII although only the TcdB_GT conjugate induced a response comparable to that obtained with CRM197. Moreover, TcdA_B2 and TcdB_GT conjugated to PSII retained the ability to elicit IgG with neutralizing activity against the respective toxins. These results are a crucial proof of concept for the development of glycoconjugate vaccines against C. difficile infection (CDI) that combine different C. difficile antigens to potentially prevent bacterial colonization of the gut and neutralize toxin activity

The development of a glycoconjugate vaccine to prevent meningitis in Africa caused by meningococcal serogroup X

Neisseria meningitidis is a major cause of bacterial meningitis worldwide, especially in the African Meningitis Belt, and has a high associated mortality. The meningococcal serogroups A, W and X have been responsible for epidemics and almost all cases of meningococcal meningitis in the Meningitis Belt over the past 12 years. Currently no vaccine is available against MenX. Since the development of a new vaccine through to licensure takes many years, this leaves Africa vulnerable to new epidemics of MenX meningitis at a time when the epidemiology of meningococcal meningitis on the continent is changing rapidly, after the recent introduction of a glycoconjugate vaccine against serogroup A. Here we report, for the first time, the development of candidate glycoconjugate vaccines against MenX and preclinical data from their use in animal studies. Following optimization of growth conditions of our seed MenX strain for polysaccharide (PS) production, a scalable purification process was developed yielding high amounts of pure MenX PS. Different glycoconjugates were synthesized by coupling MenX oligosaccharides of different chain length to CRM197 as carrier protein. Analytical methods were developed for in-process control and determination of purity and consistency of the vaccines. All conjugates induced high anti-MenX PS IgG titers in mice. Antibodies were strongly bactericidal against an African MenX isolate. These findings support the further development of glycoconjugate vaccines against MenX and their assessment in clinical trials in order to produce a vaccine against the one cause of epidemic meningococcal meningitis that currently cannot be prevented by available vaccines

A next-generation GMMA-based vaccine candidate to fight shigellosis

Abstract Shigellosis is a leading cause of diarrheal disease in low-middle-income countries (LMICs). Effective vaccines will help to reduce the disease burden, exacerbated by increasing antibiotic resistance, in the most susceptible population represented by young children. A challenge for a broadly protective vaccine against shigellosis is to cover the most epidemiologically relevant serotypes among >50 Shigella serotypes circulating worldwide. The GMMA platform has been proposed as an innovative delivery system for Shigella O-antigens, and we have developed a 4-component vaccine against S. sonnei, S. flexneri 1b, 2a and 3a identified among the most prevalent Shigella serotypes in LMICs. Driven by the immunogenicity results obtained in clinic with a first-generation mono-component vaccine, a new S. sonnei GMMA construct was generated and combined with three S. flexneri GMMA in a 4-component Alhydrogel formulation (altSonflex1-2-3). This formulation was highly immunogenic, with no evidence of negative antigenic interference in mice and rabbits. The vaccine induced bactericidal antibodies also against heterologous Shigella strains carrying O-antigens different from those included in the vaccine. The Monocyte Activation Test used to evaluate the potential reactogenicity of the vaccine formulation revealed no differences compared to the S. sonnei mono-component vaccine, shown to be safe in several clinical trials in adults. A GLP toxicology study in rabbits confirmed that the vaccine was well tolerated. The preclinical study results support the clinical evaluation of altSonflex1-2-3 in healthy populations, and a phase 1–2 clinical trial is currently ongoing

Phosphorylation of the Synthetic Hexasaccharide Repeating Unit Is Essential for the Induction of Antibodies to <i>Clostridium difficile</i> PSII Cell Wall Polysaccharide

<i>Clostridium difficile</i> is emerging worldwide as a major cause of nosocomial infections. The negatively charged PSII polysaccharide has been found in different strains of <i>C. difficile</i> and, thereby, represents an important target molecule for a possible carbohydrate-based vaccine. In order to identify a synthetic fragment that after conjugation to a protein carrier could be able to induce anti-PSII antibodies, we exploited a combination of chemical synthesis with immunochemistry, confocal immunofluorescence microscopy, and solid state NMR. We demonstrate that the phosphate group is crucial in synthetic glycans to mimic the native PSII polysaccharide; both native PSII and a phosphorylated synthetic hexasaccharide repeating unit conjugated to CRM₁₉₇ elicit comparable immunogenic responses in mice. This finding can aid design and selection of carbohydrate antigens to be explored as vaccine candidates

Epidemiological and Clinical Features of SARS-CoV-2 Variants Circulating between April-December 2021 in Italy

SARS-CoV-2 is constantly evolving, leading to new variants. We analysed data from 4400 SARS-CoV-2-positive samples in order to pursue epidemiological variant surveillance and to evaluate their impact on public health in Italy in the period of April–December 2021. The main circulating strain (76.2%) was the Delta variant, followed by the Alpha (13.3%), the Omicron (5.3%), and the Gamma variants (2.9%). The B.1.1 lineages, Eta, Beta, Iota, Mu, and Kappa variants, represented around 1% of cases. There were 48.2% of subjects who had not been vaccinated, and they had a lower median age compared to the vaccinated subjects (47 vs. 61 years). An increasing number of infections in the vaccinated subjects were observed over time, with the highest proportion in November (85.2%). The variants correlated with clinical status; the largest proportion of symptomatic patients (59.6%) was observed with the Delta variant, while subjects harbouring the Gamma variant showed the highest proportion of asymptomatic infection (21.6%), albeit also deaths (5.4%). The Omicron variant was only found in the vaccinated subjects, of which 47% had been hospitalised. The diffusivity and pathogenicity associated with the different SARS-CoV-2 variants are likely to have relevant public health implications, both at the national and international levels. Our study provides data on the rapid changes in the epidemiological landscape of the SARS-CoV-2 variants in Italy

Epidemiological and Clinical Features of SARS-CoV-2 Variants Circulating between April&ndash;December 2021 in Italy

SARS-CoV-2 is constantly evolving, leading to new variants. We analysed data from 4400 SARS-CoV-2-positive samples in order to pursue epidemiological variant surveillance and to evaluate their impact on public health in Italy in the period of April&ndash;December 2021. The main circulating strain (76.2%) was the Delta variant, followed by the Alpha (13.3%), the Omicron (5.3%), and the Gamma variants (2.9%). The B.1.1 lineages, Eta, Beta, Iota, Mu, and Kappa variants, represented around 1% of cases. There were 48.2% of subjects who had not been vaccinated, and they had a lower median age compared to the vaccinated subjects (47 vs. 61 years). An increasing number of infections in the vaccinated subjects were observed over time, with the highest proportion in November (85.2%). The variants correlated with clinical status; the largest proportion of symptomatic patients (59.6%) was observed with the Delta variant, while subjects harbouring the Gamma variant showed the highest proportion of asymptomatic infection (21.6%), albeit also deaths (5.4%). The Omicron variant was only found in the vaccinated subjects, of which 47% had been hospitalised. The diffusivity and pathogenicity associated with the different SARS-CoV-2 variants are likely to have relevant public health implications, both at the national and international levels. Our study provides data on the rapid changes in the epidemiological landscape of the SARS-CoV-2 variants in Italy