title: Protective efficacy of recombinant canine adenovirus type-2 expressing TgROP18 (CAV-2-ROP18) against acute and chronic Toxoplasma gondii infection in mice.
abstract: BACKGROUND
  The use of recombinant viral vectors expressing T. gondii antigens is a safe and efficient approach to induce immune responses against the parasite, as well as a valuable tool for vaccine development. We have previously prolonged the survival time of mice challenged with the RH strain of T. gondii by immunizing the mice with a eukaryotic vector expressing the protein ROP18 of T. gondii. We are now looking for ways to improve this vaccination strategy and enhance protection.
  
  
  METHODS
  In this study, we constructed and characterized a novel recombinant canine adenovirus type 2 expressing ROP18 (CAV-2-ROP18) of T. gondii by cytopathic effect (CPE) and indirect immunofluorescence assay (IFA) following transfection into MDCK cells. Intramuscular immunization of Kunming mice with CAV-2-ROP18 was carried out to evaluate humoral and cellular immune responses.
  
  
  RESULTS
  The vaccination of experimental mice with CAV-2-ROP18 elicited antibody production against ROP18, including high levels of a mixed IgG1/IgG2a and significant production of IFN-γ or IL-2, and displayed a significant bias towards a helper T cell type 1 (Th1) profile. Furthermore, the presence of T. gondii-specific IFN-γ-production and TNF-α-production T cells was elicited in both CD4+ and CD8+ T cell compartments. Significantly higher survival rates (40%) occurred in the experimental group, and a reduction in brain cyst burden was detected in vaccinated mice.
  
  
  CONCLUSIONS
  These results demonstrate the potential use of a CAV vector harboring the ROP18 gene in the development of a vaccine against acute and chronic toxoplasmosis.
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. 1014040084@qq.com.|Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China. 1014040084@qq.com.
authors.forename: Xiu-Zhen
authors.initials: XZ
authors.lastname: Li
authors.affiliation: Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong Province, 510642, PR China. 370125099@qq.com.
authors.forename: Xiao-Hu
authors.initials: XH
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. 1058281489@qq.com.|Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China. 1058281489@qq.com.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Xia
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. ybweng@qq.com.
authors.forename: Ya-Biao
authors.initials: YB
authors.lastname: Weng
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA. hernandezja@ufl.edu.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Hernandez
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. 632283556@qq.com.|Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China. 632283556@qq.com.
authors.forename: Li-Qing
authors.initials: LQ
authors.lastname: Tu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. 727595570@qq.com.|Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China. 727595570@qq.com.
authors.forename: Lu-Tao
authors.initials: LT
authors.lastname: Li
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. shoujunli@scau.edu.cn.|Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China. shoujunli@scau.edu.cn.
authors.forename: Shou-Jun
authors.initials: SJ
authors.lastname: Li
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. ziguoyuan@scau.edu.cn.|Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China. ziguoyuan@scau.edu.cn.
authors.forename: Zi-Guo
authors.initials: ZG
authors.lastname: Yuan
mesh_terms: D006516:Adenoviruses, Canine / Q000276:immunology*; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D007111:Immunity, Cellular / Q000276:immunology; D007273:Injections, Intramuscular; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000276:immunology*; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D013047:Specific Pathogen-Free Organisms; 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; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D019444:Vaccines, DNA; D017346:Protein Serine-Threonine Kinases; C556793:ROP18 protein, Toxoplasma gondii