Isolation and Characterizations of A Novel Recombinant scFv Antibody Against Exotoxin-A of Pseudomonas Aeruginosa
Abstract Background: Pseudomonas aeruginosa is known as the leading cause of nosocomial infections especially in people with a compromised immune system. Targeting virulence factors by neutralizing antibodies is a novel paradigm for the treatment of antibiotic-resistant pseudomonas infections.Methods: In this respect, exotoxin A is one of the most potent virulence factors in P. aeruginosa. The present study was conducted to identify a novel human scFv antibody against domain I of P. aeruginosa exotoxin A from a human scFv phage library. For this, the recombinant domain I of exotoxin A was expressed in E. coli and purified by Ni-NTA column. A novel screening procedure was conducted to prevent the elimination of rare specific clones. Based on polyclonal phage ELISA results, the fifth round of biopanning was selected to identify specific phage clones.Results: Two positive clones were found by monoclonal phage. The phage clone with high reactivity was evaluated by ELISA and western blot. The purified scFv also showed high reactivity with full length exotoxin.Conclusions: In conclusion, the purified anti-exotoxin A scFv displayed high specificity against exotoxin A. The human scFv identified can be the groundwork for development of a novel therapeutic agent for control of P. aeruginosa infections.