Abstract: Toxoplasma gondii infects nearly one third of the total population of the world, as well as warm blooded animals causing serious public health problems and economic losses in the world. Micronemes plays a key role in the invasion process of T. gondii which are used for host cell recognition, binding and motility. In this research, the researchers examined sequence variation in the microneme protein 4 (MIC4) gene sequences of 12 T. gondii isolates and reference strains from different hosts and geographical locations, then constructed the DNA vaccine expressing MIC 4 of T. gondii evaluated its immune response induced in Kunming mice. The results demonstrated that sequence variation in MIC 4 among different T. gondii isolates was low, which is a useful feature as a vaccine candidate. Immunization of mice with pVAX-MIC4 induced strong immune responses in mice as shown by significant lymphocyte proliferation, cytokine production and antibody responses as well as increased survival time of the immunized mice after challenge with tachyzoites of the virulent T. gondii RH strain, demonstrating that T. gondii MIC4 is a potential vaccine candidate against toxoplasmosis.
G.H. Peng, Z.G. Yuan, D.H. Zhou, X.H. He, C. Yan, C.C. Yin, Y. He, R.Q. Lin, H.Q. Song and X.Q. Zhu, 2010. Sequence Variation in Toxoplasma gondii MIC4 Gene and Protective Effect of an MIC4 DNA Vaccine in a Murine Model Against Toxoplasmosis. Journal of Animal and Veterinary Advances, 9: 1463-1468.