Study of cytotoxicity of Bacillus anthracis recombinant protective antigen in form of free and encapsulated by double-block PLA-PEG and PCL-PEG copolymers on the Vero cell

Background & Bacillus anthracis is the cause of the fatal anthrax. Using of vaccine is one of the effective ways to combat anthrax. Vaccines should be biocompatible and non-toxic. The purpose of this study was to investigate the effect of Bacillus anthraise recombinant protective, free and encapsulated antigen cytotoxicity by double-block PLA-PEG and PCL-PEG copolymers on the epithelial cell line of the African green monkey (Vero), in order to obtain the amount of the destructive effect of this candidate as the vaccine. In this experimental study, the Bacillus anthraise recombinant protective antigen (PA63) was expressed in E. coli and purified by nickel column affinity chromatography. Subsequently PA63 was encapsulated by PLA-PEG and PCL-PEG double-block copolymers using water-in-oil-in-water solvent evaporation method. Finally, PA63 and nanoparticles cytotoxicity test were performed using the standard MTT test on the Vero cell line. Results of the MTT test revealed the non-toxicity of the candidate vaccine. Also, the mortality rate of the cells tested against the encapsulated antigen in the nanoparticles was lower than the free antigen. According to the results, the nano-vaccine formulation can be used to reduce the toxicity of a vaccine produced and eventually acquire an effective and biocompatible recombinant vaccine.