Evaluation of the immunomodulator activity of greenpropolis extract in animals vaccinated with swine herpesvirus type 1(SuHV-1) or bovine herpesvirus type 5 (BoHV-5)
Vaccine formulation often requires the use of adjuvants which enhance or potentiatehumoral and/or cellular responses. Nowadays, many vaccines are formulated withsubstances such as aluminum hydroxide or oily emulsions, specific for veterinaryuse. However, the interest on the evaluation of natural substances with adjuvantpotential like plant extracts has grown. Propolis produced by honey bees fromexudates collected from plants has call the attention of researchers due to severalbioactive properties reported, such as antiviral, antiinflamatory and antitumoralaction. In addition, although the mechanism of action remains unknown, propolispresents activity on the immune system. The aim of this study was to evaluate theimmunomodulator activity of an ethanolic extract of Brazilian green propolis, whenused as adjuvant in inactivated vaccines against swine herpesvirus type 1 (SuHV-1)or bovine herpesvirus type 5 (BoHV-5). The addition of 5 mg/dose of the extract to avaccine with aluminum hydroxide against SuHV-1 increased the humoral immuneresponse of mice, when compared to the same vaccine without propolis (P<0,01).This effect was more evident when the vaccine was diluted (1:4 and 1:8). The raise inneutralizing antibodies titer, expressed in log2, went from 3 to 4.48 and 2.18 to 4.48,respectively, suggesting that the smaller the antigenic mass or less immunogenic theantigen, more pronounced is the adjuvant effect of propolis. When propolis was usedon its own with the antigen, an increase in the titer of neutralizing antibodiesdetermined by seroneutralization was not observed. Besides increasing the humoralimmune response, the use of propolis also increased the cellular response,increasing mRNA synthesis of IFN-? in mice splenocytes, measured by RT-PCR.This increase was also observed in the group of animals immunized only with antigenand propolis, unlike the effect observed on the humoral response. The adjuvanteffect of propolis was also demonstrated when mice were challenged with 31.6 lethaldoses of SuHV-1, 21 days after the second inoculation. The addition of propolis tothe vaccine with aluminum hydroxide increased the percentage of protected animals,especially in the higher dilutions, comparing to the vaccine without propolis. Similarresult was observed in the group of animals vaccinated only with propolis andantigen. The association of 40 mg/dose of ethanolic extract of green propolis to theoily vaccine against BoHV-5 increased titer of bovine neutrali zing antibodies(P<0,01), when compared to a vaccine without propolis. Thirty days after the seconddose the titer went from 35 to 54, and after the third dose it increased from 43 to 67.In addition, there was an increase in the percentage of animals with titer above 32.The inclusion of 20 mg/dose of the extract did not alter the humoral response. The chromatographic analysis of propolis by HPLC showed high levels of phenoliccompounds as artepillin C and cynamic acid derived, which may be the mainsubstances with action on the immunologic system. Therefore, green propolisethanolic extract acted as an adjuvant substance, increasing humoral and cellularimmune responses in mice and humoral response in bovines, improving theefficiency of experimental vaccines.
Advisor:Odir Antônio Dellagostin; Telmo Vidor; Fabio Pereira Leivas Leite
School:Universidade Federal de Pelotas
Source Type:Master's Thesis
Date of Publication:02/28/2007