ABSTRACT
At present,there are no ideal drugs and measures in the treatment and prevention of toxoplasmosis.The develop-ment of safe,convenient,and strong protective nucleic acid vaccine is an important strategy for prevention and control of toxo-plasmosis.The rhoptry protein(ROP)is a large class of proteins secreted by Toxoplasma gondii.ROPs play an important role in the invasion of host cells,the formation of parsitophorous vacuole(PV)and the regulation of proliferation by T.gondii.Thus, ROPs become the most promising candidates of vaccine.In this paper,we summarize the important members of the ROPs,the expression vector and the immunogenicity and immunoprotection of the nucleic acid vaccine in animal experiments.
ABSTRACT
Objective To study the protective effect of ROP2 nuclei acid vaccine in mice.Methods Forty-two BALB/c mice were divided into three groups.Each mouse in experiment group was injected with 50 ?g recombinant plasmid pc-DNA3-ROP2 through musculus quadriceps fexoris.In control groups,each mouse was injected with 50 ?g blank plasmid pc-DNA3 and with 50 ?l PBS respectively.All mice were immunized for three times with an interval of three weeks.The volume was doubled for the final injection in the two plasmid groups.Blood,spleens and lymph nodes of 4 mice in each group were taken for the detection of CD4+,CD8+ T cells and cytokines 2 weeks after the final immunization.The rest mice in 3 groups were challenged with 500 tachyzoites of Toxoplasm gondii RH strain for further observation.Results The vaccine induced strong cellular and humoral immune response.The titer of antibody in serum was high after inoculation and recognized ROP2 protein antigen expressed in vitro.The lymphocyte phenotype was analyzed.CD4+ T cells proliferated sharply(69.5?3.4)%,and the ratio of CD4+/CD8+ increased considerably by(4.69?1.32)%(P