Glycolytic Enzymes as Potential Vaccine Candidates for Streptococcus Pneumoniae

Strategic Insights -

Streptococcus pneumoniae is a leading cause of various infectious diseases worldwide, including otitis media, sinusitis, pneumonia, bacteremia, and meningitis. Current vaccines are often limited by the number of capsular polysaccharides that can be included, making pneumococcal proteins an attractive alternative for vaccine candidates. Researchers in Israel have identified glycolytic enzymes associated with the cell surface of Streptococcus pneumoniae as antigenic in humans and capable of eliciting protective immune responses in mice. This breakthrough has significant implications for the development of novel vaccine candidates against this pathogen.

Key Takeaways:

  • Researchers in Israel have identified 17 glycolytic enzymes that are antigenic in humans and capable of eliciting protective immune responses in mice.
  • Two of these enzymes, fructose-bisphosphate aldolase (FBA) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), showed an increasing antibody response with age in children and were used to immunize mice.
  • Mouse antibodies elicited to the recombinant FBA and GAPDH were cross-reactive with several genetically unrelated strains of different serotypes, conferring protection against respiratory challenge with virulent pneumococci.
  • The FBA used in this study does not have a human ortholog and warrants further investigation as a candidate for a pneumococcal vaccine.
  • The immunoproteomics-based approach used in this study appears to be a suitable tool for identifying novel S. pneumoniae vaccine candidates.

Statistics:

  • 150 soluble proteins were identified from an enriched cell wall fraction of S. pneumoniae WU2 using 2D gel electrophoresis.
  • 17 proteins were found to be antigenic in humans and capable of eliciting protective immune responses in mice.
  • Five proteins, including FBA and GAPDH, were expressed in Escherichia coli and used to immunize mice.
  • Mouse antibodies elicited to the recombinant FBA and GAPDH were cross-reactive with 70% of the tested strains.

Sources:

  • Ling E, et al. "Glycolytic enzymes associated with the cell surface of Streptococcus pneumoniae are antigenic in humans and elicit protective immune responses in the mouse." Clin Exp Immunol, 138(2):290-298, 2004.
  • Yaffa Mizrachi Nebenzahl, Department of Microbiology and Immunology and The Pediatric Infectious Disease Unit, Soroka University Medical Center, Beer Sheva, 84105, Israel. Email: ymizr@bgumail.bgu.ac.il.