Vaccination with recombinant adenovirus expressing multi-stage antigens of Toxoplasma gondii by the mucosal route induces higher systemic cellular and local mucosal immune responses than with other vaccination routes

Wang, Ting; Yin, Huiquan; Li, Yan; Zhao, Lingxiao; Sun, Xiahui; Cong, Hua

To evaluate the protective immunity, six mice of each group were given an intraperitoneal injection of 1 · 10 3 tachyzoites of T. gondii RH strain at 4 weeks after vaccination. The survival rates of mice immunized via different routes are shown in Figure 3 . The mice immunized with Ad-UMAS via i.m., i.o., and i.n. showed an almost 50% survival rate and lower survival rates of 40% were found in the i.v. and s.c. immunization groups 28 days after challenge. All the control mice died within 8 days. The level of protective effect against chronic infection was evaluated by counting cysts in the brains of mice challenged with 20 cysts of the PRU strain of T. gondii (Fig. 3 ). An obvious reduction in the burden of brain cyst was detected in all the immunized mice compared with the control mice (p < 0.05). The brain cyst numbers in the oral and nasal immunization groups were significantly reduced to 459 ± 34 and 398 ± 61, respectively, which is much lower than the other immunization groups with injection in muscle (569 ± 23), via the venous route (892 ± 51), and via the subcutaneous route (675 ± 65) (p < 0.05).