Imunological evaluation of Pneumococcal Triad Histidine Protein D (PhTD) in mice.

• Grant number: 13/02234-9
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2013
• End date: January 31, 2015
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Michelle Darrieux Sampaio Bertoncini
• Grantee: Greiciely André de Oliveira
• Host Institution: Universidade São Francisco (USF). Campus Bragança Paulista. Bragança Paulista , SP, Brazil

Abstract

Streptococcus pneumoniae is a major cause of pneumonia, meningitis, sepsis, otitis media amongst others diseases. It is responsible for high mortality worldwide, being more aggressive in children and the elderly especially in developing countries. Due to the increase in the numbers of antibiotic resistant strains, vaccines play an important role in preventing disease. They are currently based on capsular polysaccharides conjugated or not to carrier proteins. However, the high structural and biochemical variability of capsules limit coverage. This fact, coupled with the steady increase in cases of pneumococcal disease by serotypes not included in the vaccines, ultimately reduce the effectiveness of these formulations, especially in high-risk groups. In order to develop an alternative vaccine against Streptococcus pneumoniae, with broad coverage and cost-effective, several pneumococcal proteins that comprise virulence factors have been studied as potential candidates for combating S. pneumoniae. PhT and Ply are currently the subject of intense study in several animal models with promising results. Both have had their immunogenicity evaluated either alone or coadministered with other pneumococcal proteins. In addition, both proteins have been described as able to interact with the complement system. This system plays an important role in host defense. Therefore this study aims to characterize the immune response to a vaccine of hybrid PhTD-P1D1, as well as to investigate the functionality of this response in complement deposition, anti-hemolytic properties and opsonophagocytosis, besides analyzing the protection conferred by this hybrid in mice after systemic and colonization challenges.