title: Immune responses of pigs immunized with a recombinant porcine reproductive and respiratory syndrome virus expressing porcine GM-CSF.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) has spread worldwide, causing huge economic losses to the swine industry. The current PRRSV vaccines have failed to provide broad protection against various strains. Granulocyte macrophage colony-stimulating factor (GM-CSF), an efficacious adjuvant, has been shown to enhance the immunogenicity of various vaccines. The purpose of this study was to construct a recombinant live attenuated PRRSV that expresses porcine GM-CSF (pGM-CSF) and evaluate the immune responses of pigs immunized with the recombinant virus. The results showed that the recombinant PRRSV was successfully rescued and had similar growth properties to parental virus grown in Marc-145 cells. The recombinant virus was stable for 10 passages in cell culture. Pigs intramuscularly immunized with the recombinant virus produced a similar humoral response to that elicited using parental virus. With regard to cell-mediated immunity assessed in peripheral blood, the recombinant virus induced higher proportion of CD4(+)CD8(+) double-positive T cells (DPT), higher IFN-γ level at 0 and 7 days post-challenge (DPC), and lower viremia at 21 DPC than pigs immunized with parental virus. These results indicate that recombinant PRRSV expressing pGM-CSF can induce a significant higher cellular immune response and reduce the persistent infection compared pigs vaccinated with the parental virus. This is first report of evaluation of immune response in pigs elicited by a recombinant live attenuated PRRSV expressing porcine GM-CSF. It may represent a novel strategy for future development of genetic engineered vaccines against PRRSV infection.
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China.
authors: Zhijun
authors: Z
authors: Li
authors: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agriculture Science, Harbin, Heilongjiang Province 150001, China.
authors: Gang
authors: G
authors: Wang
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China.
authors: Yan
authors: Y
authors: Wang
authors: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agriculture Science, Harbin, Heilongjiang Province 150001, China.
authors: Chong
authors: C
authors: Zhang
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China.
authors: Baicheng
authors: B
authors: Huang
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China.
authors: Qiongyi
authors: Q
authors: Li
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China.
authors: Liangliang
authors: L
authors: Li
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China.
authors: Biyun
authors: B
authors: Xue
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China.
authors: Peiyang
authors: P
authors: Ding
authors: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agriculture Science, Harbin, Heilongjiang Province 150001, China.
authors: Xuehui
authors: X
authors: Cai
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China. Electronic address: wangchengbao@nwsuaf.edu.cn.
authors: Chengbao
authors: C
authors: Wang
authors: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China; Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, China Ministry of Agriculture, Yangling, Shaanxi 712100, China. Electronic address: zhouem@nwsuaf.edu.cn.
authors: En-Min
authors: EM
authors: Zhou
mesh_terms: D000276:Adjuvants, Immunologic / Q000235:genetics; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D016207:Cytokines / Q000097:blood; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000276:immunology; D007111:Immunity, Cellular; D008168:Lung / Q000473:pathology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D034421:Sus scrofa / Q000276:immunology*; D013552:Swine; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology; D014766:Viremia / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary
chemical_list: D000276:Adjuvants, Immunologic; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D016207:Cytokines; D011994:Recombinant Proteins; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; D016178:Granulocyte-Macrophage Colony-Stimulating Factor
keywords: Infectious clone; PRRSV; Porcine GM-CSF; Vaccine