title: Recombinant canine adenovirus type-2 expressing TgROP16 provides partial protection against acute Toxoplasma gondii infection in mice.
abstract: We previously demonstrated that the survival time of BALB/c mice challenged with Toxoplasma gondii RH strain was prolonged by immunising the mice with a eukaryotic vector expressing the protein ROP16 of T. gondii. Building upon previous findings, we are exploring improved vaccination strategies to enhance protection. In this work, a novel recombinant canine adenovirus type 2 expressing ROP16 (CAV-2-ROP16) of T. gondii was constructed and identified to express ROP16 in Madin-Darby canine kidney cells (MDCK) cells by western blot (WB) and indirect immunofluorescence (IFA) assays. Intramuscular immunisation of BALB/c mice with CAV-2-ROP16 was performed to evaluate the humoral and cellular immune responses. This vaccination triggered significant humoral and cellular responses, including ROP16-stimulated lymphoproliferation (P<0.05). Compared to control groups, the CAV-2-ROP16 immunised mice had high production of IFN-γ, IL-2 and IL-12 (P<0.05), with a predominance of IgG2a production, but not IL-10 (P>0.05), revealing that a predominant Th1-type response had developed. The cell-mediated cytotoxic activity with high levels of IFN-γ and TNF-α was significantly increased in both CD4+and CD8+T-cell compartments in the mice immunised with CAV-2-ROP16 (P<0.05), compared to three control groups. In addition, when immunised mice were challenged with the RH strain of T. gondii, they showed a significantly increased survival rate (25%) 80days post infection compared with control mice that all died within seven days (P<0.05). The 25% protection rate elicited by the recombinant virus CAV-2-ROP16 has not been achieved in the field of anti-T. gondii vaccination until now. Our work presents the successful use of recombinant virus CAV-2-ROP16 in vaccination protocols to protect against intraperitoneal challenge with the virulent RH strain of T. gondii. This system was shown to be extremely efficient in eliciting humoral and cellular immune responses that led to a significant improvement in survival time in mice.
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Xiu-Zhen
authors.initials: XZ
authors.lastname: Li
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lv
authors.affiliation: College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province 163319, PR China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Phytobiotechnology Research Foundation Institute (PRF), Catholic University of Cameroon, 999108 Bamenda, Cameroon.
authors.forename: Kenneth Yongabi
authors.initials: KY
authors.lastname: Anchang
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Auwalu Yusuf
authors.initials: AY
authors.lastname: Abdullahi
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Liqing
authors.initials: L
authors.lastname: Tu
authors.affiliation: Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Xia
authors.affiliation: College of Agriculture, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Xiu-Xiang
authors.initials: XX
authors.lastname: Zhang
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Weili
authors.initials: W
authors.lastname: Feng
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Lu
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors.forename: Shoujun
authors.initials: S
authors.lastname: Li
authors.affiliation: Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China. Electronic address: ziguoyuan@scau.edu.cn.
authors.forename: Zi-Guo
authors.initials: ZG
authors.lastname: Yuan
mesh_terms: D006516:Adenoviruses, Canine / Q000235:genetics*; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D016207:Cytokines / Q000097:blood; D004285:Dogs; D005260:Female; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology*; D014124:Toxoplasmosis, Animal / Q000276:immunology* / Q000469:parasitology; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D016207:Cytokines; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D019444:Vaccines, DNA; D011505:Protein-Tyrosine Kinases; C552524:Rop16 protein, Toxoplasma gondii
keywords: CAV-2-ROP16; Mice; Recombinant virus; Toxoplasma gondii; Vaccine