Characterization of the domain of fibronectin-binding protein of I of Streptococcus pyogenes responsible for elicitation of a protective immune response
Fibronectin-binding protein I (SfbI) represents a major adhesin ofStreptococcus pyogenes. Mice were intranasally immunized with recombinant proteins spanning different portions of SfbI to identify the minimal fragment able to elicit a protective response against a lethal challenge with S. pyogenes. The strongest cellular responses and the highest levels of antigen-specific secretory immunoglobulin A (IgA) were detected in mice immunized with the fibronectin-binding region of SfbI. In contrast, animals vaccinated with a polypeptide spanning the aromatic and proline-rich regions showed the highest titers and fastest IgG response in serum. Vaccination with either SfbI without a membrane anchor and signal peptide or a polypeptide encompassing its fibronectin-binding regions resulted in efficient protection against heterologous challenge (60% and 80%, respectively), whereas the use of a polypeptide lacking this region conferred marginal protection (10%) with respect to the control group (0%). These results demonstrate that the fibronectin-binding region of SfbI is a promising candidate antigen for developing anti-S. pyogenes vaccines.
Schulze, K., Medina, E., Talay, S. R., Towers, R. J., Chhatwal, G. S. & Guzman, C. A. (2001). Characterization of the domain of fibronectin-binding protein of I of Streptococcus pyogenes responsible for elicitation of a protective immune response. Infection and Immunity, 69 (1), 622-625.