Extracellular vesicles as a vaccine against Streptococcus pneumoniae

• Grant number: 25/06749-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2025
• End date: April 30, 2027
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Eliane Namie Miyaji
• Grantee: Adriano Palharini de Araújo
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 24/18870-6 - Evaluation of extracellular vesicles as vaccine against Streptococcus pneumoniae: role of virulence factors and two-component systems, AP.R

Abstract

Streptococcus pneumoniae is the causative agent of several diseases such as otitis media, sinusitis, pneumonia, sepsis and meningitis. Polysaccharide conjugate vaccines led to a significant reduction in invasive pneumococcal disease caused by serotypes present in the vaccine formulation, but substitution by non-vaccine serotypes was observed. Furthermore, after a period of decrease in pneumococcal disease during the adoption of non-pharmacological measures during the COVID-19 pandemic, different countries are starting to report cases of pneumococcal disease above pre-pandemic levels. New formulations are therefore needed to control diseases caused by the pneumococcus. This project aims to evaluate pneumococcal extracellular vesicles (EVs) as a vaccine formulation capable of inducing serotype-independent protection. EVs will be produced from the non-encapsulated isolate Rx1 and used for immunization and protection studies in mice. The role of the protein antigens PspA (Pneumococcal surface protein A) and PspC (Pneumococcal surface protein C) in the protection induced by EVs will be evaluated through immunization with EVs derived from the Rx1-pspAKO and Rx1-pspCKO strains. Since these are antigens with a certain degree of variability, strains derived from Rx1 expressing different variants of PspA and PspC will also be used. The data obtained by the project may provide important information for the development of a low-cost, broad-coverage vaccine against infections caused by S. pneumoniae. (AU)