Avaliação de Bacillus toyonensis como bioadjuvante em vacina recombinante

Abstract

Bacillus toyonensis is a probiotic bacterium that exerts immunomodulatory effect, capable to enhance the effectiveness of vaccines. The objective of this study was to investigate the immunomodulatory effect of B. toyonensis in mice vaccinated with the recombinant glycoprotein D of bovine herpesvirus type 5. Mice were randomly divided into eight experimental groups. The complete B.t group received supplementation with the probiotic during all the experimental period. The 7days B.t group was supplemented seven days prior to the first vaccine dose. The sc live Esp group received an inoculation of viable spores of B. toyonensis subcutaneously (sc) simultaneously to the vaccine. The sc inact Esp group received an inoculation of inactivated spores via sc simultaneously to the vaccine. The live Esp+rgD group received the vaccine antigen associated with living spores. The inact Esp+rgD group received the vaccine antigen associated with inactivated spores. The rgD+Al(OH)3 and rgD+PBS, were control groups, did not received supplementation with the probiotic, nor spore inoculation. The humoral immune response was evaluated by ELISA and serum neutralization. The animals of all groups responded to the vaccine with the total IgG antibody production. The groups supplemented with probiotic (complete B.t and 7days B.t) as well as the ones that received the spore inoculation simultaneously to the vaccine (sc live Esp and sc inact Esp) showed higher levels of antibodies, showing statistical difference (p≤0,05) when compared to the unsupplemented ones. The groups that received the vaccine antigen associated to the spores (live Esp+rgD and inact Esp+rgD) showed lower antibodies levels when compared to the supplemented groups. The results indicate that the probiotic B. toyonensis has an immunomodulatory effect in mice vaccinated with the recombinant glycoprotein D of bovine herpesvirus type 5, establishing an alternative to increase the vaccines efficacy.