Toxoplasma gondii rhomboid protein 1 (TgROM1) is a potential vaccine candidate against toxoplasmosis

Infection with the intracellular protozoan parasite Toxoplasma gondii causes serious public health problems and is of great economic importance worldwide. The rhomboid proteins which are responsible for adhesion and invasion of host cells have been suggested as vaccine candidates against toxoplasmosis. A DNA vaccine (pVAX-ROM1) encoding T. gondii rhomboid protein 1 (TgROM1) gene was constructed and the immune response and protective efficacy of this vaccine against lethal challenge in BALB/c mice were evaluated. The results indicated that specific antibody and lymphocyte proliferative responses were elicited in mice receiving pVAX-ROM1. The production levels of IFN-γ, IL-2, IL-4, and IL-10, as well as the percentage of CD4(+) cells in mice vaccinated with pVAX-ROM1 were significantly increased respectively, compared to controls receiving either pVAX1 alone or PBS. After lethal challenge, the mice immunized with pVAX-ROM1 showed an increased survival time compared with the mice in the controls. Our data suggested that a DNA vaccine pVAX-ROM1 encoding T. gondii rhomboid protein 1 triggered strong humoral and cellular responses, and prolonged survival time against T. gondii infection in BALB/c mice.