Toxoplasma gondii immune mapped protein-1 (TgIMP1) is a novel vaccine candidate against toxoplasmosis.

Immune mapped protein1 (IMP1) is a new protective protein in apicomplexan parasites, and exists in Toxoplasma gondii. In the present study, a DNA vaccine expressing IMP1 of T. gondii was constructed and the immune response induced in BALB/c mice was evaluated. The coding sequence of IMP1 was inserted into the eukaryotic expression vector pcDNA 3.1(+), resulting a recombinant plasmid pcDNA-IMP1, which was used to immunize BALB/c mice intramuscularly. After immunization, the immune response was evaluated using lymphoproliferative assay, and cytokine and antibody measurements. The mice were challenged with tachyzoites of the virulent T. gondii RH strain 14th day after the last immunization to observe the survival time. The results showed that the group immunized with pcDNA-IMP1 developed a high level of specific antibody responses against Escherichia coli expressed recombinant TgIMP1, with high IgG antibody titers, predominance of IgG2a production, a strong lymphoproliferative response, and significant levels of IFN-γ, IL-2, IL-4 and IL-10 production compared with the control groups. These results demonstrate that pcDNA-IMP1 could elicit strong humoral and Th1 immune responses. Immunized mice showed a significantly (15.8 ± 6 days) prolonged survival time compared with control mice, which died within 7 days of challenge infection. These results suggest that IMP1 is a promising vaccine candidate against toxoplasmosis. Copyright Â