title: Toxoplasma gondii: protective immunity induced by rhoptry protein 9 (TgROP9) against acute toxoplasmosis.
abstract: Toxoplasma gondii rhoptry protein 9 (ROP9) is involved in the early stages of host invasion, and contains B cell epitopes. The aim of this study was to evaluate the immune protective efficacy of a DNA vaccine encoding TgROP9 gene against acute T. gondii infection in mice. A DNA vaccine (pVAX-ROP9) encoding TgROP9 inserted into eukaryotic expression vector pVAX I was constructed, and the efficacy of intramuscular vaccination of Kunming mice with pVAX-ROP9 was analyzed. Mice immunized with pVAX-ROP9 induced a high level of specific anti-T. gondii antibodies, as well as a mixed IgG1/IgG2a response with predominance of IgG2a production. Also, injection of pVAX-ROP9 induced a specific lymphocyte proliferative responses and Th1-type cellular immune response with production of IFN-γ and interleukin-2. The percentages of CD4+ and CD8+ T cells were significantly increased in mice immunized with pVAX-ROP9, compared to empty vector, PBS or blank controls. Immunization with pVAX-ROP9 significantly (P<0.05) prolonged survival time (12.9±2.9days) after challenge infection with the virulent T. gondii RH strain (Type I), compared with the control groups which died within 6days. DNA vaccination with pVAX-ROP9 triggered strong humoral and cellular responses, and induced effective protection in mice against acute T. gondii infection, indicating that TgROP9 is a promising vaccine candidate against acute toxoplasmosis.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China.
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province 163319, PR China.
authors.forename: Zhong-Yuan
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Department of Infectious Diseases, Clinical Institute, and Institute of Medical Microbiology and Immunology, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark.
authors.forename: Eskild
authors.initials: E
authors.lastname: Petersen
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China.
authors.forename: Si-Yang
authors.initials: SY
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China.
authors.forename: Hui-Qun
authors.initials: HQ
authors.lastname: Song
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province 163319, PR China. Electronic address: xingquanzhu1@hotmail.com.
authors.forename: Xing-Quan
authors.initials: XQ
authors.lastname: Zhu
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis* / Q000097:blood; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D015870:Gene Expression; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D010957:Plasmids; D016052:Protozoan Vaccines / Q000276:immunology*; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology*; D014124:Toxoplasmosis, Animal / Q000276:immunology / Q000517:prevention & control*; D019444:Vaccines, DNA / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016207:Cytokines; D007074:Immunoglobulin G; D008565:Membrane Proteins; D016052:Protozoan Vaccines; C449007:ROP9 protein, Toxoplasma gondii; D019444:Vaccines, DNA
keywords: DNA vaccine; Mice; Protective immunity; Rhoptry protein 9 (ROP9); Toxoplasma gondii; Toxoplasmosis