Intranasal Immunization with Mucosal Complex Vaccine Protects Mice Against Toxoplasma gondii / 中国寄生虫学与寄生虫病杂志

ABSTRACT

Objective To study the mucosal and systemic immune response after intranasal immunization with mucosal complex vaccine for Toxoplasma gondii,and to observe the protective effect on mice. Methods The mucosal complex vaccine was made of soluble tachyzoite antigen (STAg) and cholera toxin (CT),which were mixed and dissolved in PBS (1 ml PBS containing 1 mg STAg and 50 ?g CT). Fifty-two BALB/c mice were randomly divided into two groups immunized group and control. Mice were intranasally immunized with 20 ?l mucosal complex vaccine (20 ?g STAg and 1?g CT) per mouse twice at an interval of two weeks,while the control mice were given PBS solution instead. Six mice of each group were killed by dislocation of cervical vertebra on day 14 after the last immunization. The specific IgG antibodies in serum and IgA in feces were detected by ELISA. Lymphocytes in spleen,Peyer's patches (PP) and intestinal intraepithelial lymphocyte(IEL) were isolated and counted. Percentage of CD4+ and CD8+ T cells was determined by immunocytochemistry. Other mice were challenged intragastrically each with 4?104 tachyzoites of RH strain Toxoplasma gondii on day 14 after the last immunization. Their health condition was observed and the number of tachyzoites in liver and brain was determined microscopically on the 30 th day after challenge. Results IgG antibodies in serum and IgA antibodies in feces of immunized mice were higher than the control (P