Induction of neutralizing antibodies in mice immunized with an amino-terminal polypeptide of Streptococcus mutans P1 protein produced by a recombinant Bacillus subtilis strain
2010
Tavares, Milene B. | Silva, Bruno M. | Cavalcante, Rafael C.M. | Souza, Renata D. | Luiz, Wilson B. | Paccez, Juliano D. | Crowley, Paula J. | Brady, L Jeannine | Ferreira, Luís C.S. | Ferreira, Rita C.C.
The oral pathogen Streptococcus mutans expresses a surface protein, P1, which interacts with the salivary pellicle on the tooth surface or with fluid-phase saliva, resulting in bacterial adhesion or aggregation, respectively. P1 is a target of protective immunity. Its N-terminal region has been associated with adhesion and aggregation functions and contains epitopes recognized by efficacious antibodies. In this study, we used Bacillus subtilis, a gram-positive expression host, to produce a recombinant N-terminal polypeptide of P1 (P1₃₉₋₅₁₂) derived from the S. mutans strain UA159. Purified P1₃₉₋₅₁₂ reacted with an anti-full-length P1 antiserum as well as one raised against intact S. mutans cells, indicating preserved antigenicity. Immunization of mice with soluble and heat-denatured P1₃₉₋₅₁₂ induced antibodies that reacted specifically with native P1 on the surface of S. mutans cells. The anti-P1₃₉₋₅₁₂ antiserum was as effective at blocking saliva-mediated aggregation of S. mutans cells and better at blocking bacterial adhesion to saliva-coated plastic surfaces compared with the anti-full-length P1 antiserum. In addition, adsorption of the anti-P1 antiserum with P1₃₉₋₅₁₂ eliminated its ability to block the adhesion of S. mutans cells to abiotic surfaces. The present results indicate that P1₃₉₋₅₁₂, expressed and purified from a recombinant B. subtilis strain, maintains important immunological features of the native protein and represents an additional tool for the development of anticaries vaccines.
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