Determination of Immunological Properties of Pseudomonas aeroginosa PA103, by Serum Bactericidal Assay & ELIS

Background: Exotoxin A (ExoA) is one of the most known and important virulence factors of Pseudomonas aeruginosa. This toxin is the cause of ADP-ribosylation in eukaryutic Elongation Factor- 2 (EF-2), which results in the protein synthesis inhibition. Recent studies had shown immunostimulational characteristics of detoxified the ExoA. Our aim in this study was to evaluate the immunological properties of detoxified ExoA by Serum Bactericidal assay, in comparison with ELISA. Methods: The production of ExoA was done on the ExoA-producing strain, Pseudomonas aeruginosa PA103, provided by Pasteur institute of Iran. After culture in semi-industrial scale, it was detoxified and purified by dialysis. The dialysate was injected to mice and rabbit. After 3weeks, the total sera were collected. Serum bactericidal assay & ELISA were performed. Results: The results had shown a significant increase of antibodies against detoxified ExoA of 1/16 and antibody in ELISA method. Also, this has shown more antigenecity & immunogenosity by SBA method. Conclusion: To conclude the study that has been done here, SBA has much higher advantages than ELISA, in determining the immunological properties of Exo A. Furthermore, since Exo A could act as a hapten, many other subunits from other bacteria or viruses could be conjugated on Exo A and form multi-target vaccines.