| Toxoplasma gondii can cause severe and even fatal disease in human beings and animals.
Effective vaccines may contribute to control toxoplasmosis. GRA14, a novel secreted
dense granule protein of T. gondii, has been proposed as a vaccine candidate
due to its intervacuolar transport and unique topology in the parasitophorous vacuole
membrane. In this study, we constructed a DNA vaccine encoding GRA14 of T. gondii.
BALB/c mice were immunized intramuscularly three times at 2 week intervals and
challenged with T. gondii RH strain 5 weeks later. The immune responses were evaluated
using lymphocyte proliferation assay, cytokine and antibody measurements. In
addition, the survival times and parasite load of mice challenged with the virulent
T. gondii RH strain were evaluated. The results showed that the mice immunized with
pcGRA14 induced both enhanced specific humoral and Th1 cellular immune responses,
and also mice immunized with the pcGRA14 showed an increased survival
time and decreased parasite load compared with control groups (P<.05). The results
indicated, for the first time, that the GRA14 is a potential DNA vaccine against
toxoplasmosis. |