Synthesis of PEG-PLA Block Copolymer Nanospheres Containing Mixed Recombinant Proteins of Protective Antigen and Lethal Factor of Bacillus anthracis

Anthrax is a zoonotic disease and vaccine production is one way to protect people against this bacterium. This study investigates the application of copolymer nanocapsule (PEG-PLA) systems with controlled release specificity for a recombinant protective antigen and lethal factor of Bacillus anthracis to provide a vaccine candidate.

In this experimental study, the dual solvent evaporation emulsion method was used to produce nanocapsules. Moreover, zeta potential and size of nanoparticles, loading efficiency of nanoparticles, recombinant protein release pattern, the probable effect of PLA-PEG nanoparticle production on the shelf life of recombinant proteins were investigated in this study. Mice were used as test and control samples for antibody production and immune response evaluation.
(Ethic code: 9727250)

The results of this study showed that mixed proteins (LFD1+PAD4) loaded on PEG-PLA block copolymer had an average size of 109 nm, the zeta potential of -27.7 mV, and PDI=0.394. In this study, it was shown that the release of these antigens was carried out in two stages of rapid and slow release. The release of the proteins was estimated at about 20% on the first day and 78% on the 49th day. The titers of antibodies produced in the serum of the mouse groups against these antigens at defined intervals were significantly different from each other.

The results of this study suggest the application of PEG-PLA block copolymer nanocapsules containing mixed recombinant proteins of protective antigen and lethal factor of Bacillus anthracis. Due to less degradation and more protection of antigen activity in nanoparticles, compared to traditional methods, as well as fewer repeat injections, higher specificity, reduced side effects, lower cost, and slower release rate, the use of nanoparticles is a good option to replace traditional methods.