ARS | Publication request: Immunoproteomic analysis of the antibody response obtained in tilapia following immunization with a Streptococcus iniae vaccine

Submitted to: American Fisheries Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2009
Publication Date: June 8, 2009
Citation: Lafrentz, B.R., Klesius, P.H. 2009. Immunoproteomic analysis of the antibody response obtained in tilapia following immunization with a Streptococcus iniae vaccine. American Fisheries Society (Fish Health Section). p. 15.

Technical Abstract: Streptococcus iniae is one of the most economically important Gram-positive pathogens in cultured fish species worldwide. Research has shown that vaccination is a tool that can be used in the prevention of streptococcal disease. The USDA-ARS patented S. iniae vaccine has been demonstrated to be efficacious, and protection appears to be mediated by specific anti-S. iniae antibodies. In the present study, an immunoproteomic approach was utilized to identify proteins of S. iniae that stimulated specific antibody production in Nile tilapia (Oreochromis niloticus) following immunization. Groups of tilapia were immunized by intraperitoneal injection with either the S. iniae vaccine or mock-immunized, and at 4 weeks post-immunization sera samples were obtained from individual fish for subsequent analyses. Immunization of tilapia with the S. iniae vaccine stimulated specific antibody responses against the bacterium, as determined by ELISA, that were significantly different than that of the control group. Western blot analysis using sera from treatment and control groups revealed that immunized fish exhibited antibodies specific for proteins of S. iniae. For increased resolution of bacterial proteins, whole-cell lysate proteins of S. iniae were separated by 2D-PAGE and were probed with pooled sera samples. Immunogenic proteins were excised from 2D-PAGE gels and submitted for identification by mass spectrometry methods. The proteins identified in this study may be important protein antigens for efficacy of the S. iniae vaccine.