Development and evaluation of a multi-epitope subunit vaccine against group B Streptococcus infection

ABSTRACT

Streptococcus agalactiae (Group B Streptococcus, GBS) is a multi-host pathogen, even causing life-threatening infections in newborns. Vaccination with GBS crossed serotypes vaccine is one of the best options for long-term infection control. Here we built a comprehensive in silico epitope-prediction workflow pipeline to design a multivalent multiepitope-based subunit vaccine containing 11 epitopes against Streptococcus agalactiae (MVSA). All epitopes in MVSA came from the proteins which were antigenic-confirmed, virulent-associated, surface-exposed and conserved in ten GBS serotypes. The in-silico analysis showed MVSA had potential to evoke strong immune responses and enable worldwide population coverage. To validate MVSA protection efficacy against GBS infection, immune protection experiments were performed in a mouse model. Importantly, MVSA induced a high titre of antibodies, significant proliferation of mice splenocytes and elicited strong protection against lethal-dose challenge with a survival rate of 100% in mice after three vaccinations. Meanwhile, the polyclonal antibody against MVSA did not only inhibit for growth of GBS from six crucial serotypes in vitro, but also protect 100% naive mice from GBS lethal challenge. These active and passive immunity assay results suggested that MVSA could therefore be an efficacious multi-epitope vaccine against GBS infection.

KEYWORDS:

• Group B Streptococcus
• immunoinformatic
• multi-epitope vaccine
• immune protection
• B cell epitope
• T cell epitope

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical approval

All animal studies were approved by the Experimental Animal Welfare and Ethics Committee of Nanjing Agricultural University (Approval ID: XYXK(SU)2021-0086), and were performed according to Animal Welfare Agency Guidelines.

Additional information

Funding

This work was supported by the Guidance Foundation, the Sanya Institute of Nanjing Agricultural University [grant number NAUSY-MS12]; the Fundamental Research Funds for the Central Universities [grant number KJQN201618]; the Youth Foundation of National Natural Science Foundation of China [grant number 31502085].