Prevention of pneumococcal disease in mice immunized with conserved surface-accessible proteins

J Hamel, N Charland, I Pineau, C Ouellet… - Infection and …, 2004 - Am Soc Microbiol
J Hamel, N Charland, I Pineau, C Ouellet, S Rioux, D Martin, BR Brodeur
Infection and immunity, 2004Am Soc Microbiol
The development of a vaccine against Streptococcus pneumoniae has been complicated by
the existence of at least 90 antigenically distinct capsular serotypes. Common protein-based
vaccines could represent the best strategy to prevent pneumococcal infections, regardless of
serotype. In the present study, the immunoscreening of an S. pneumoniae genomic library
allowed the identification of a novel immune protein target, BVH-3. We demonstrate that
immunization of mice with BVH-3 elicits protective immunity against experimental sepsis and …
Abstract
The development of a vaccine against Streptococcus pneumoniae has been complicated by the existence of at least 90 antigenically distinct capsular serotypes. Common protein-based vaccines could represent the best strategy to prevent pneumococcal infections, regardless of serotype. In the present study, the immunoscreening of an S. pneumoniae genomic library allowed the identification of a novel immune protein target, BVH-3. We demonstrate that immunization of mice with BVH-3 elicits protective immunity against experimental sepsis and pneumonia. Sequence analysis revealed that the bvh-3 gene is highly conserved within the species. Since the BVH-3 protein shows homology at its amino-terminal end with other pneumococcal proteins, it was of interest to determine if protection was due to the homologous or to the protein-specific regions. Immunoprotection studies using recombinant BVH-3 and BVH-3-related protein fragments as antigens allowed the localization of surface-exposed and protective epitopes at the protein-specific carboxyl termini, thus establishing that BVH-3 is distinct from other previously reported protective protein antigens. Immunization with a chimeric protein comprising the carboxyl-terminal regions of BVH-3 and of a BVH-3-related protein improved the protection by targeting two surface pneumococcal components. Thus, BVH-3 and the chimeric protein hold strong promise as vaccine components to control pneumococcal disease.
American Society for Microbiology