Immune response induced in mice by a hybrid rPotD-PdT pneumococcal protein

Author(s)

Converso, Thiago Rojas ; Goulart, Cibelly ; Rodriguez, Dunia ; Souza Guerra, Maria Eduarda ; Darrieux, Michelle ; Leite, Luciana C. C.

• Document type: Journal article
• Source: PLoS One; v. 17, n. 8, p. 14-pg., 2022-08-22.

Abstract

Streptococcus pneumoniae is a human pathogen that colonizes the naso and/or oropharynx and can cause otitis, pneumonia, bacteremia and meningitis. To broaden the protection against pneumococcus, several pneumococcal proteins have been investigated as vaccine candidates. In this study we analyzed the immunological response induced by mouse subcutaneous immunization with a fusion of the Polyamine transport protein D (PotD) and a pneumolysin derivative (PdT), resulting in a hybrid rPotD-PdT protein. Immunization of mice with rPotD-PdT induced increased production of nitric oxide, indicating a higher innate immune response. In agreement, immunization of mice with the hybrid protein was more immunogenic than the individual proteins or their combination, eliciting higher antibody levels. The anti-rPotD-PdT IgG displayed increased binding onto the pneumococcal surface. Furthermore, the anti-rPotD-PdT antisera promoted superior opsonophagocytosis as compared with the other tested formulations. However, despite that the encouraging results in vitro, immunization with the hybrid was not sufficient to induce protection against sepsis with a highly virulent pneumococcal strain. taken together, the results suggest that hybrid proteins are an interesting strategy, able to promote improved immune responses, but the inclusion of other antigens may be necessary to promote protection against invasive infections caused by this bacterium. (AU)

• FAPESP's process: 12/04286-3 - The study of polyamines transporter, PotD, as a vaccine antigen against Streptococcus pneumoniae
• Grantee: Thiago Rojas Converso
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 17/24832-6 - Development of vaccines based on recombinant BCG: Tuberculosis, Pertussis, Pneumococcus and Schistosoma
• Grantee: Luciana Cezar de Cerqueira Leite
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 19/23566-6 - Evaluation of the role of polyamine transporters in biofilm formation by Streptococcus pneumoniae and Klebsiella pneumoniae
• Grantee: Thiago Rojas Converso
• Support Opportunities: Regular Research Grants