Immunogenicity Evaluation of Recombinant Staphylococcus aureus Enterotoxin B (rSEB) and rSEB-loaded Chitosan Nanoparticles Following Nasal Administration

Staphylococcal enterotoxin B (SEB), apotent superantigen, is responsible for many disorders caused by Staphylococcus aureus. With regard to the appearance of multidrug-resistant strains of the bacteria, there is a great need to develop an efficient vaccine against this pathogen. In the present study, the immunogenicity of recombinant SEB was evaluated following nasal administration to BABLB/c mice. Indeed, the rSEB protein was entrapped into chitosan nanoparticles and the immunogenicity of nano-formulation was investigated. SEB protein was expressed in E. coli BL21 (DE3) and purified by using a nickel column. Chitosan nanoparticles were synthesized in the presence of rSEB; using the ionic gelation technique. Synthesized NPs containing rSEB and bare rSEB were administered to mice nasally. Serum and stool IgG and IgA antibody showed that both formulations were able to evoke the mice's immune responses and there was no significant difference between them. Results of the toxin neutralization test on Vero cells indicated that the sera of the immunized mice had an inhibitory effect on the growth of these cells (p<0.001). Nasal administration of bare rSEB could efficiently simulate the mice's immune system and nano-delivery of this protein via nasal route had not a significant impact on its immunogenicity improvement.