RESUMO
OBJECTIVE: To observe the splenocytes immune response elicited by different concentrations of recombinant Toxoplasma gondii profiling (rTgPRF) through the nasal route, and determine the optimal dose. METHODS: Fifty female BALB/c mice were randomly divided into 5 groups. The immunized groups were intranasally administered with 10, 20, 30 µg or 40 µg of rTgPRF that was separately dissolved in 20 µl of phosphate-buffered saline (PBS) on days 0, 14, and 21 respectively, while the control mice were given PBS solution instead. Two weeks after the last immunization, all mice were killed. Under asceptic conditions, the spleens from the immunized mice were dissected, and then the splenocyte proliferative responses in vitro were tested by CCK-8 kit. The levels of IFN-γ, IL-2, IL-4 and IL-10 of splenocyte culture supernatant were detected by ELISA. RESULTS: Compared to the control group, the splenocytes from the 30 µg and 40 µg groups exhibited a significantly higher proliferative response to rTgPRF (P < 0.05), and SI from the 30 µg rTgPRF group was higher than that from the 40 µg group (P < 0.05). The levels of IFN-γ in all the immunized groups (P < 0.05) and IL-2 in the 20, 30 µg and 40 µg groups were significantly stronger than those in the control (P < 0.05), and the 30 µg group presented the highest concentrations of IFN-γ (P < 0.01) and IL-2 (P < 0.01). There were no statistical differences among the groups in the levels of IL-4 and IL-10. CONCLUSIONS: The intranasal immunization with rTgPRF can induce the splenocyteproliferation and Th1-type mediated immunity. The best immunized dose is confirmed as 30 µg.
