Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 13 1 2025 02 16 40 45 Shahrzad Aliniay Sharafshadehi Department of Microbiology, Faculty of Advanced Science And Technology, Tehran Medical Science, Islamic Azad University,Tehran, Iran. Neda shadvar Department of microbiology and parasitology, school of medicine,Bushehr university of medical sciences, Bushehr,Iran Seyyed Nematollah Seify Department of Medical Microbiology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran Mohammad Reza Mohammadi Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Marziyeh Taher Sarjam Molecular cell biology_Microbial Biotechnology, Islamic Azad University Rasht Branch, Iran Saina Najafi Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Javad Fathi Department of Microbiology, Faculty of Medicine, Shahed University, Tehran, Iran Mahdi S.Sadati Department of Microbiology, Faculty of Biological Sciences, Islamic Azad University Tehran-North Branch, Tehran, Iran Nahal Hadi Department of Medical Bacteriology and Virology, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. 2024 11 17 2024 11 25 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. https://jmb.tums.ac.ir/index.php/jmb/article/view/548