TARGETING GROUP A STREPTOCOCCUS WITH A RECOMBINANT CHIMERIC VACCINE: INTEGRATING SCPA AND SPEA FRAGMENTS

AbstractObjective: To develop a vaccine against group A streptococci (Streptococcus pyogenes, GAS), the causative agent of a broad spectrum of infections with varying severity.Methods: The expression vectors pET27 and pQE30 were utilized to clone genes encoding recombinant proteins, which were subse...

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Main Authors: Nadezhda Vladlenovna Duplik, Galina Fedorovna Leontieva, Tatiana Anatolievna Kramskaya, Kseniya Petrovna Bogatireva, Tatiana Vitalievna Gupalova, Elena Alekseevna Bormotova, Irina Vladimirovna Koroleva, Alexander Nikolaevich Suvorov
Format: Article
Language:Russian
Published: St. Petersburg branch of the Russian Association of Allergologists and Clinical Immunologists 2019-08-01
Series:Медицинская иммунология
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Online Access:https://www.mimmun.ru/mimmun/article/view/3138
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Summary:AbstractObjective: To develop a vaccine against group A streptococci (Streptococcus pyogenes, GAS), the causative agent of a broad spectrum of infections with varying severity.Methods: The expression vectors pET27 and pQE30 were utilized to clone genes encoding recombinant proteins, which were subsequently affinity-purified. Female mice were immunized subcutaneously twice with the purified polypeptides (20 μg/mouse) formulated with Alum adjuvant (2:1) at three-week intervals. Immune sera were analyzed using ELISA to evaluate antigen-specific responses. Three weeks after the final immunization, mice were challenged intraperitoneally with GAS M1 serotype at a dose of 5x10^7 CFU/mouse.  Vaccination efficacy was determined by comparing bacterial clearance in vaccinated versus control animals, assessed by bacterial loads in the spleen at 3 and 15 hours post-infection.Results: The vaccine candidate is a hybrid recombinant protein comprising fragments from two essential GAS virulence factors: C5a peptidase (ScpA) and SpeA exotoxin. T- and B-cell epitopes from conserved regions, common across multiple GAS serotypes, were identified and included in the construct using bioinformatics tools.The integration of these epitopes is designed to confer broad-spectrum protection against GAS strains carrying exotoxin, particularly those linked to invasive infections. Immunogenicity studies in mice revealed a robust humoral immune response targeting both components of the hybrid protein. Further evaluation of protective efficacy demonstrated accelerated bacterial clearance in vaccinated animals, with the SpeA fragment playing a significant protective role.Conclusion: These findings underscore the potential of this recombinant chimeric vaccine as a promising candidate for the prevention of group A streptococcal infections, addressing the critical need for effective prophylactic strategies against GAS-associated diseases.
ISSN:1563-0625
2313-741X