The immune response against Toxoplasma gondii in BALB/c mice induced by mannose-modified nanoliposome of excreted/secreted antigens.

This study aimed to compare the immune response against Toxoplasma gondii (T. gondii) in BALB/c mice induced by excreted/secreted (E/S) antigens and mannose-modified nanoliposome of E/S antigens. Here, E/S antigens and mannose-modified nanoliposome of E/S antigens were firstly prepared, and then BALB/c female inbred mice were separately immunized. In the next step, anti-E/S antigen antibodies and the relative expression levels of IL-10 and IL-12 mRNA were detected by ELISA and real-time PCR, respectively. After immunization, mice were intraperitoneally challenged with 102 tachyzoites of T. gondii, and the survival rate was recorded. The ELISA analysis showed significant differences between the levels of anti-E/S antigen antibodies in the mice immunized by E/S antigens and those immunized by mannose-modified nanoliposome of E/S antigens at days 7, 10, 20, 25, and 30 (P < 0.05). Real-time PCR analysis showed that the relative expression of IL-10 was significantly decreased during 20 days. Yet, the relative expression of IL-12 was significantly increased during 20 days (P < 0.05). In T. gondii challenge test, significant differences were found between the survival rates of mice immunized by E/S antigens and mice immunized by mannose-modified nanoliposome with E/S antigens. This project evidenced that mannose-modified nanoliposome of E/S antigens induced a more powerful immune response against T. gondii in BALB/c mice when compared with excreted/secreted antigens alone.