Contribution of the complement system to protection elicited by pneumococcal vaccines including PhTD, PspA, PspC and pneumolysin

• Grant number: 16/07249-2
• Support type: Regular Research Grants
• Duration: October 01, 2017 - March 31, 2020
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Michelle Darrieux Sampaio Bertoncini
• Grantee: Michelle Darrieux Sampaio Bertoncini
• Home Institution: Universidade São Francisco (USF). Campus Bragança Paulista. Bragança Paulista , SP, Brazil

Abstract

Streptococcus pneumoniae is responsible for a high number of deaths worldwide, affecting mostly young children and the elderly, particularly in developing countries. The currently available vaccines, composed of polysaccharydes alone or conjugated to protein carriers have high production costs and confer limited coverage. Therefore, many pneumococcal proteins have been evaluated as potential vaccine candidates with promising results. However, in order to maximize the vaccine coverage, it is necesary to include multiple antigens in the formulation. Due to the pivotal role of the complement system in immunity against pneumococcus, the present work will determine the protective potential of proteins that inhibit complement deposition on the bacterial surface, combined or fused in chimeras. This strategy would eliminate the compensatory effects of these antigens, rendering a higher protective efficacy to the vaccine. The selected proteins were PhTD and its N- and C-terminal fragments, the N-terminal region of PspA family 1, PlD1 and PspC. The immune response induced by the vaccines will be investigated, and protection will be assessed in mouse models of colonization and sepsis. The interaction between PhTD and factor H will be evaluated by ELISA and confirmed by FACS. C3b deposition on pneumococcal surface and bacterial phagocytosis in vitro will also be analysed. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ANDRE, GREICIELY O.; ASSONI, LUCAS; RODRIGUEZ, DUNIA; LEITE, LUCIANA C. C.; DOS SANTOS, THAISY E. P.; FERRAZ, LUCIO F. C.; CONVERSO, THIAGO R.; DARRIEUX, MICHELLE. Immunization with PhtD truncated fragments reduces nasopharyngeal colonization by Streptococcus pneumoniae. Vaccine, v. 38, n. 26, p. 4146-4153, MAY 27 2020. Web of Science Citations: 0.