| The primary aim of this study was to investigate the protective effect against Toxoplasma gondii infection following intranasally administrated mice with STAg in association with gamma interferon (IFN-γ) or propolis, and determine the optimal dose of IFN-γor propolis as adjuvant for intranasal immunization. The next goal was to compare the protective role of IFN-γand propolis intranasally administrated, and explore the combined effect of propolis with IFN-γas adjuvant for intranasal immunization. The method to determine the optimal dose of IFN-γor propolis as adjuvant: Seventy or sixty 5-to 6-week-old BALB/c mice were randomly divided into five groups, each group were immunized intranasally two times at 14-day intervals with 20μg STAg and different doses of IFN-γ(250U, 500U, 1000U, 2000U) or propolis (5μg, 10μg, 20μg, 40μg). The PBS containing 4×104 tachyzoites of RH strain in each 0.5-ml volume were orally administered to all animals on day 10 after the last immunization. The health and survival of mice were observed day by day. Survivors were killed on day 29 after infection, the tachyzoites in livers and brains were counted, the number of MLN and spleen T lymphocytes were determined, the content of IgA antibody in the feces,lung wash and IgG in the sera were detected by ELISA. The method to compare IFN-γwith propolis as adjuvant: Sixty 5-to 6-week-old female BALB/c mice were randomly divided into four groups, fifteen mice of each group were immunized intranasally two times at 14-day intervals with 20μg STAg alone, 20μg STAg plus 40μg propolis, 20μg STAg plus 1000U IFN-γor 20μg STAg plus 40μg propolis+1000U IFN-γ. The PBS containing 4×104 tachyzoites of RH strain in each 0.5-ml volume were orally administered to all animals on day 10 after the last immunization. Weight and survival of mice were recorded day by day. Survivors were killed on day 43 after infection, the tachyzoites of brains and livers were counted, the CD4+ and CD8+ T lymphocytes of IEL,Payer's patches and spleen were determined by SABC immunohistochemistry, the content of IgA antibody in the feces, nasopharynx wash, lung wash, vaginal wash, sera and IgG in the sera were detected by ELISA. Survival rate of mice was rising with the increasing dose of IFN-γ, the survival rate of STAg plus 1000U IFN-γgroup was 93%, which was the highest among groups. The tachyzoites had an incline to decrease, which were significantly smaller in the groups of STAg plus 1000U IFN-γor STAg plus 2000U than that of STAg group (P<0.05). Proliferative responses were observed in MLN and spleen T lymphocytes, and the MLN cells in the groups of STAg plus 1000U IFN-γand STAg plus 2000U IFN-γwere obviously higher than that of STAg group (P<0.01). The content of IgA antibody in the feces,lung wash and IgG in the sera in the groups of STAg plus 1000U IFN-γand STAg plus 2000U were obviously higher than that of STAg group (P<0.05). Survival rate of mice was rising with the increasing dose of propolis which was the highest in the groups of STAg plus 40μg propolis among groups. The tachyzoites in brain and liver had an incline to decrease, which was the smallest in the group of STAg plus 40μg propolis among all groups. Proliferative responses were observed in MLN and spleen T lymphocytes, and the T lymphocytes in MLN and spleen of the group of STAg plus 40μg propolis were obviously higher than that of STAg group (P<0.05). The level of IgA antibodyin the feces, lung wash and IgG in the sera were rising with the increasing dose of propolis,but no significant differentiation from STAg group. The experimental result of the comparison between IFN-γand propolis: Weight of thymus and spleen in the groups of STAg plus IFN-γand STAg plus propolis+IFN-γwere obviously higher than that of the STAg group, the tachyzoites had an incline to decrease, which were significantly smaller than that of STAg group, proliferative responses were observed in IEL, Payer's patches and spleen T lymphocytes, the level of CD4~+ T lymphocyte in Payer's patches and the level of CD... |
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