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Abstract
The different technology platforms used to make poultry vaccines are reviewed. Vaccines based on classical technologies are either live attenuated or inactivated vaccines. Genetic engineering is applied to design by deletion, mutation, insertion, or chimerization, genetically modified target microorganisms that are used either as live or inactivated vaccines. Other vaccine platforms are based on one or a few genes of the target pathogen agent coding for proteins that can induce a protective immune response ("protective genes"). These genes can be expressed in vitro to produce subunit vaccines. Alternatively, vectors carrying these genes in their genome or nucleic acid-based vaccines will induce protection by in vivo expression of these genes in the vaccinated host. Properties of these different types of vaccines, including advantages and limitations, are reviewed, focusing mainly on vaccines targeting viral diseases and on technologies that succeeded in market authorization.
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Liu JL, Teng M, Zheng LP, Zhu FX, Ma SX, Li LY, Zhang ZH, Chai SJ, Yao Y, Luo J. Emerging Hypervirulent Marek's Disease Virus Variants Significantly Overcome Protection Conferred by Commercial Vaccines. Viruses 2023; 15:1434. [PMID: 37515122 PMCID: PMC10385823 DOI: 10.3390/v15071434] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
As one of the most important avian immunosuppressive and neoplastic diseases, Marek's disease (MD), caused by oncogenic Marek's disease virus (MDV), has caused huge economic losses worldwide over the past five decades. In recent years, MD outbreaks have occurred frequently in MD-vaccinated chicken flocks, but the key pathogenic determinants and influencing factors remain unclear. Herein, we analyzed the pathogenicity of seven newly isolated MDV strains from tumor-bearing chickens in China and found that all of them were pathogenic to chicken hosts, among which four MDV isolates, SDCW01, HNXZ05, HNSQ05 and HNSQ01, were considered to be hypervirulent MDV (HV-MDV) strains. At 73 days of the virus infection experiment, the cumulative incidences of MD were 100%, 93.3%, 90% and 100%, with mortalities of 83.3%, 73.3%, 60% and 86.7%, respectively, for the four viruses. The gross occurrences of tumors were 50%, 33.3%, 30% and 63.3%, respectively, accompanied by significant hepatosplenomegaly and serious atrophy of the immune organs. Furthermore, the immune protection effects of four commercial MD vaccines against SDCW01, CVI988, HVT, CVI988+HVT, and 814 were explored. Unexpectedly, during the 67 days of post-virus challenge, the protection indices (PIs) of these four MD vaccines were only 46.2%, 38.5%, 50%, and 28%, respectively, and the birds that received the monovalent CVI988 or HVT still developed tumors with cumulative incidences of 7.7% and 11.5%, respectively. To our knowledge, this is the first demonstration of the simultaneous comparison of the immune protection efficacy of multiple commercial MD vaccines with different vaccine strains. Our study revealed that the HV-MDV variants circulating in China could significantly break through the immune protection of the classical MD vaccines currently widely used. For future work, there is an urgent need to develop novel, more effective MD vaccines for tackling the new challenge of emerging HV-MDV strains or variants for the sustainable control of MD.
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Affiliation(s)
- Jin-Ling Liu
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs of China & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Man Teng
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs of China & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Lu-Ping Zheng
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs of China & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Feng-Xia Zhu
- Zhumadian Center for Animal Disease Control and Prevention, Zhumadian 463000, China
| | - Shu-Xue Ma
- Suiping Center for Animal Disease Control and Prevention, Zhumadian 463100, China
| | - Lin-Yan Li
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs of China & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471003, China
| | - Zhi-Hui Zhang
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs of China & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Shu-Jun Chai
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs of China & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Yongxiu Yao
- The Pirbright Institute & UK-China Centre of Excellence for Research on Avian Diseases, Pirbright, Ash Road, Guildford GU24 0NF, Surrey, UK
| | - Jun Luo
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs of China & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471003, China
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Sun A, Zhao X, Zhu X, Kong Z, Liao Y, Teng M, Yao Y, Luo J, Nair V, Zhuang G, Zhang G. Fully Attenuated meq and pp38 Double Gene Deletion Mutant Virus Confers Superior Immunological Protection against Highly Virulent Marek's Disease Virus Infection. Microbiol Spectr 2022; 10:e0287122. [PMID: 36350141 PMCID: PMC9769808 DOI: 10.1128/spectrum.02871-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022] Open
Abstract
Marek's disease virus (MDV) induces immunosuppression and neoplastic disease in chickens. The virus is controllable via an attenuated meq deletion mutant virus, which has the disadvantage of retaining the ability to induce lymphoid organ atrophy. To overcome this deficiency and produce more vaccine candidates, a recombinant MDV was generated from the highly virulent Md5BAC strain, in which both meq and a cytolytic replication-related gene, pp38, were deleted. Replication of the double deletion virus, Md5BAC ΔmeqΔpp38, was comparable with that of the parental virus in vitro. The double deletion virus was shown to be fully attenuated and to reduce lymphoid organ atrophy in vivo. Crucially, Md5BAC ΔmeqΔpp38 confers superior protection against highly virulent virus compared with a commercial vaccine strain, CVI988/Rispens. Transcriptomic profiling indicated that Md5BAC ΔmeqΔpp38 induced a different host immune response from CVI988/Rispens. In summary, a novel, effective, and safe vaccine candidate for prevention and control of MD caused by highly virulent MDV is reported. IMPORTANCE MDV is a highly contagious immunosuppressive and neoplastic pathogen. The virus can be controlled through vaccination via an attenuated meq deletion mutant virus that retains the ability to induce lymphoid organ atrophy. In this study, we overcame the deficiency by generating meq and pp38 double deletion mutant virus. Indeed, the successfully generated meq and pp38 double deletion mutant virus had significantly reduced replication capacity in vivo but not in vitro. It was fully attenuated and conferred superior protection efficacy against very virulent MDV challenge. In addition, the possible immunological protective mechanism of the double deletion mutant virus was shown to be different from that of the gold standard MDV vaccine, CVI988/Rispens. Overall, we successfully generated an attenuated meq deletion mutant virus and widened the range of potential vaccine candidates. Importantly, this study provides for the first time the theoretical basis of vaccination induced by fully attenuated gene-deletion mutant virus.
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Affiliation(s)
- Aijun Sun
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Xuyang Zhao
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Xiaojing Zhu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Zhengjie Kong
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Yifei Liao
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Man Teng
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, People’s Republic of China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, People’s Republic of China
| | - Yongxiu Yao
- Viral Oncogenesis Group,The Pirbright Institute, Pirbright, Surrey, United Kingdom
- UK-China Centre of Excellence for Research on Avian Diseases, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Jun Luo
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, People’s Republic of China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, People’s Republic of China
| | - Venugopal Nair
- Viral Oncogenesis Group,The Pirbright Institute, Pirbright, Surrey, United Kingdom
- UK-China Centre of Excellence for Research on Avian Diseases, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Guoqing Zhuang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Gaiping Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- Key Laboratory of Animal Immunology, Ministry of Agriculture and Rural Affairs & Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, People’s Republic of China
- UK-China Centre of Excellence for Research on Avian Diseases, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
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Song C, Yang Y, Hu J, Yu S, Sun Y, Qiu X, Tan L, Meng C, Liao Y, Liu W, Ding C. Safety and Efficacy Evaluation of Recombinant Marek's Disease Virus with REV-LTR. Vaccines (Basel) 2020; 8:vaccines8030399. [PMID: 32698460 PMCID: PMC7564749 DOI: 10.3390/vaccines8030399] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 12/19/2022] Open
Abstract
Recently, chickens vaccinated with the CVI988/Rispens vaccine showed increased tumor incidence. Moreover, many strains of Marek's disease virus (MDV) that were naturally integrated with the long terminal repeat (LTR) of the avian reticuloendotheliosis virus (REV) have been isolated, which means it is necessary to develop a new vaccine. In this study, two LTR sequences were inserted into Rispens to construct a recombinant MDV (rMDV). Then, the safety and efficacy of rMDV were evaluated separately in chickens. The growth rate curves showed that the insertion of REV-LTR into MDV enabled a faster replication in vitro than Rispens. Chickens immunized with high or repeated dose rMDV had no MD clinical signs. Further, no tumor, tissue lesions, or evident pathological changes were observed in the chicken organs. Polymerase chain reaction (PCR) and virus isolation revealed that rMDV had the ability to spread horizontally to non-immunized chickens and had no impact on the environment. After five passages in chickens, there were no obvious lesions, and the LTR insertion was stable. There were also no deletions or mutations, which indicates that rMDV is safe in chickens. In addition, rMDV has an advantage over Rispens against vvMDV Md5 at low doses. All results demonstrate that the transgenic strain of rMDV with REV-LTR can be used as a live attenuated vaccine candidate.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Chan Ding
- Correspondence: ; Tel.: +86-21-34293441; Fax: +86-21-34293461
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Sun P, Cui N, Liu L, Su S, Cheng Z, Chen R, Li Y, Cui Z. Attenuation of a recombinant Marek's disease virus lacking the meq oncogene and evaluation on its immune efficacy against Marek's disease virus. Poult Sci 2020; 99:1939-1945. [PMID: 32241474 PMCID: PMC7587640 DOI: 10.1016/j.psj.2019.11.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/15/2019] [Accepted: 11/15/2019] [Indexed: 11/30/2022] Open
Abstract
SC9-2 is a recombinant Marek's disease virus (MDV) strain lacking the meq oncogene. Previous study demonstrated that SC9-2 virus provides good protection against challenge with a very virulent MDV rMd5, but it induces immunosuppressive effects in specific pathogen-free (SPF) chickens. In the present study, SC9-2 was serially passaged on chicken embryo fibroblast (CEF) cell cultures. The pathogenicity and immune efficacy of SC9-2/10th and SC9-2/40th against rMd5 were evaluated. Animal experimental results showed that SC9-2/10th and SC9-2/40th showed no lethality or tumorigenicity in SPF chickens. Body weight of chickens inoculated with SC9-2/40th were significantly higher than that of the chickens inoculated with SC9-2/10th but lower than that of the uninoculated controls. The severity of bursa and thymus atrophy (BTA) and spleen enlargement in SC9-2/40th-inoculated chickens were also weaker than the SC9-2/10th-inoculated ones but stronger than the uninoculated controls. Chickens inoculated with SC9-2/40th and SC9-2/10th showed similar antibody levels induced by H9N2 subtype avian influenza virus/Newcastle disease virus inactivated vaccines, both of which were lower than the uninoculated controls. Replication of SC9-2/40th was significantly lower than SC9-2/10th in feather follicle epithelium (FFE) of infected chickens. The immune protection index of SC9-2/40th was also lower than that of SC9-2/10th, but the difference was not significantly, and both of which were significant higher than that of the commercial MDV vaccine CVI988/Rispens. The results of our studies demonstrated that SC9-2/40th showed weaker severity of BTA, spleen enlargement, and body weight loss and lower replication level in FFE than SC9-2/10th in SPF chickens. However, SC9-2/40th was able to confer better immune protection as compared with CVI988/Rispens vaccination in SPF chickens. In conclusion, serially attenuation of SC9-2 in CEFs reduced the lymphoid organ atrophy and replication in SPF chickens, and the immune protective efficacy of attenuated viruses was still superior than CVI988/Rispens.
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Affiliation(s)
- Peng Sun
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention; College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Ning Cui
- Shandong Key Laboratory of Animal Disease Control & Breeding; Institute of Animal Husbandry and Veterinary, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Linqing Liu
- China Animal Disease Control Center, Beijing, 100125 China
| | - Shuai Su
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention; College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China.
| | - Ziqiang Cheng
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention; College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Ruiai Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.
| | - Yanpeng Li
- Zhaoqing Institute of Biotechnology Co., Ltd., Zhaoqing, Guangdong 526238, China
| | - Zhizhong Cui
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention; College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China
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Zhang Y, Cui N, Han N, Wu J, Cui Z, Su S. Depression of Vaccinal Immunity to Marek's Disease by Infection with Chicken Infectious Anemia Virus. Front Microbiol 2017; 8:1863. [PMID: 29018431 PMCID: PMC5622928 DOI: 10.3389/fmicb.2017.01863] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/12/2017] [Indexed: 01/26/2023] Open
Abstract
Marek’s disease (MD) has been occurring with increasing frequency in chickens in recent years. To our knowledge, however, there has been no report of the very virulent plus (vv+) MD virus (MDV) field isolate in China. Studies have shown that dual infection with immunosuppressive viruses such as chicken infectious anemia virus (CIAV) occurs frequently in chickens developing MD. In this study, we performed a designed set of in vivo experiments, which comprised five different groups of chickens, including the group of CVI988/Rispens-vaccinated chickens, the groups of CVI988/Rispens-vaccinated chickens infected with MDV or CIAV or both viruses (MDV and CIAV), and the group of MDV-challenged chickens. The effects of CIAV dual infection on the immunization of commercial MDV vaccine CVI988/Rispens were evaluated. The results show that infection of the SD15 strain of CIAV significantly reduced the weight and antibody titers to avian influenza virus (AIV)/Newcastle disease virus (NDV) inactivated vaccines of chickens immunized with the CVI988/Rispens, and resulted in the atrophy of thymus/bursa and the enlargement of spleen. The CVI988/Rispens vaccination conferred good immune protection for chickens challenged with 2000 PFU of the GX0101 strain of MDV. However, dual infection with SD15 significantly reduced the body weight, antibody titers induced by AIV/NDV inactivated vaccines and protective index of CVI988/Rispens, and resulted in the aggravation of the immunosuppression, mortality, and viremia of GX0101 in CVI988/Rispens-immunized/GX0101-challenged chickens. Overall, CIAV infection significantly reduced the protective effects of the CVI988/Rispens vaccine against MDV, implying that concurrent infection with CIAV may be a major contributor in the frequent attacks of MD in China in recent years.
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Affiliation(s)
- Yankun Zhang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Ning Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, China.,Institute of Animal Husbandry and Veterinary, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Ni Han
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Jiayan Wu
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Zhizhong Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China
| | - Shuai Su
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
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Zhang Y, Liu C, Yan F, Liu A, Cheng Y, Li Z, Sun G, Lv H, Wang X. Recombinant Gallid herpesvirus 2 with interrupted meq genes confers safe and efficacious protection against virulent field strains. Vaccine 2017; 35:4695-4701. [PMID: 28754487 DOI: 10.1016/j.vaccine.2017.07.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 12/21/2022]
Abstract
Gallid herpesvirus 2 (GaHV-2) continuously evolves, which reduces the effectiveness of existing vaccines. To construct new GaHV-2 candidate vaccines, LMS, which is a virulent GaHV-2 field strain isolated from diseased chicken flocks in Southwest China in 2007, was modified such that both copies of its meq oncogene were partially deleted. The resulting virus, i.e., rMSΔmeq, was characterized using PCR and sequencing. To evaluate the safety and protective efficacy of rMSΔmeq, specific pathogen-free (SPF) chickens were inoculated with 2000 plaque forming units (pfu) and 20,000pfu of rMSΔmeq immediately after hatching. All birds grew well during the experimental period, and none of the challenged chickens developed Marek's disease-associated lymphoma. In addition, the rMSΔmeq- and CVI988/Rispens-vaccinated SPF chickens were challenged with 1000 pfu and 5000 pfu of the representative virulent GaHV-2 Md5 strain and 1000 pfu of the variant GaHV-2 strains LCC or LTS. The results showed that the rMSΔmeq strain provided complete protection, which was similar to that provided by the CVI988/Rispens vaccine (protective index (PI) of 95.5) when challenged with a conventional dose of the Md5 strain. However, rMSΔmeq provided a PI of 90.9 when challenged with 5000 pfu of the Md5 strain, which was significantly higher than that provided by the CVI988/Rispens vaccine (54.5). rMSΔmeq provided a PI of 86.4 against LCC, which was equal to that provided by the CVI988/Rispens vaccine (81.8). In addition, rMSΔmeq provided a PI of 100 against LTS, which was significantly higher than that provided by the CVI988/Rispens vaccine (68.2). Altogether, the rMSΔmeq virus provided efficient protection against representative and variant GaHV-2 strains. In conclusion, the rMSΔmeq virus is a safe and effective vaccine candidate for the prevention of Marek's disease and is effective against the Chinese variant GaHV-2 strains.
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Affiliation(s)
- Yanping Zhang
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
| | - Changjun Liu
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China.
| | - Fuhai Yan
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
| | - Ailing Liu
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
| | - Yun Cheng
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
| | - Zhijie Li
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
| | - Guorong Sun
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
| | - Hongchao Lv
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
| | - Xiaomei Wang
- Avian Immunosuppressive Diseases Division, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, PR China.
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8
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Marek's disease vaccines: Current status, and strategies for improvement and development of vector vaccines. Vet Microbiol 2016; 206:113-120. [PMID: 28038868 DOI: 10.1016/j.vetmic.2016.11.024] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/19/2016] [Accepted: 11/23/2016] [Indexed: 11/24/2022]
Abstract
Marek's disease (MD) is a lymphoproliferative viral disease of chickens, which has been controlled through vaccination since 1969. MD vaccines protect against tumors but do not provide sterilizing immunity, and thus it is generally believed that their use has contributed to increase virulence of field strains with the ability to cause MD in vaccinated chickens. Traditional methods of developing vaccines, like cell culture attenuation, have proved unsuccessful for the development of improved vaccines to protect against highly virulent MD virus (MDV) field strains. With the advent of recombinant DNA technology, it is now possible to study MDV gene function and develop rational vaccines that protect against highly pathogenic strains. In addition, the long term protection conferred by MD vaccines, their excellent safety profile, their efficacy when administered early (at hatch or in ovo), and their ability to overcome maternal antibodies, has made MDV an excellent candidate vector to protect not only against MD but also against other important viral poultry diseases. In this review we will discuss the current status of MD vaccines and their use as vector vaccines to control important viral poultry diseases.
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Mays JK, Black-Pyrkosz A, Spatz S, Fadly AM, Dunn JR. Protective efficacy of a recombinant bacterial artificial chromosome clone of a very virulent Marek's disease virus containing a reticuloendotheliosis virus long terminal repeat. Avian Pathol 2016; 45:657-666. [PMID: 27258614 DOI: 10.1080/03079457.2016.1197376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Marek's disease virus (MDV), an alphaherpesvirus, causes Marek's disease (MD), a lymphoproliferative disease in poultry characterized by T-cell lymphomas, nerve lesions, and mortality. Vaccination is used worldwide to control MD, but increasingly virulent field strains can overcome this protection, driving a need to create new vaccines. Previous studies revealed that insertion of reticuloendotheliosis virus (REV) long terminal repeat (LTR) into a bacterial artificial chromosome (BAC) clone of a very virulent strain of MDV, Md5, rendered the resultant recombinant virus, rMd5 REV-LTR BAC, fully attenuated in maternal antibody positive (Mab+) chickens at passage 40. In the current study, the protective efficacy of rMd5 REV-LTR BAC was evaluated. First, passage 70 was identified as being fully attenuated in maternal antibody negative chickens and chosen as the optimal passage level for use in protective efficacy studies. Second, three protective efficacy trials were conducted comparing the rMd5 REV-LTR p70 BAC to the CVI988/Rispens vaccine. Groups of Mab+ and Mab- 15I5 × 71 chickens were vaccinated in ovo at 18 days of embryonation or intra-abdominally at day of hatch, and challenged at 5 days post-hatch with the vv+MDV strain 686. Vaccination at day of hatch and in ovo with rMd5 REV-LTR p70 BAC protected chickens against MDV-induced bursa and thymic atrophy, but did not provide the same level of protection against MD tumours as that afforded by the commercial vaccine, CVI988/Rispens.
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Affiliation(s)
- Jody K Mays
- a Avian Disease and Oncology Laboratory, United States Department of Agriculture , Agricultural Research Service , East Lansing , MI , USA
| | - Alexis Black-Pyrkosz
- a Avian Disease and Oncology Laboratory, United States Department of Agriculture , Agricultural Research Service , East Lansing , MI , USA
| | - Stephen Spatz
- b US National Poultry Research Center, United States Department of Agriculture , Agricultural Research Service , Athens , GA , USA
| | - Aly M Fadly
- a Avian Disease and Oncology Laboratory, United States Department of Agriculture , Agricultural Research Service , East Lansing , MI , USA
| | - John R Dunn
- a Avian Disease and Oncology Laboratory, United States Department of Agriculture , Agricultural Research Service , East Lansing , MI , USA
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10
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Luan H, Wang Y, Li Y, Cui Z, Chang S, Zhao P. Development of a real-time quantitative RT-PCR to detect REV contamination in live vaccine. Poult Sci 2016; 95:2023-9. [DOI: 10.3382/ps/pew147] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2016] [Indexed: 11/20/2022] Open
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11
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Cui N, Su S, Sun P, Zhang Y, Han N, Cui Z. Isolation and pathogenic analysis of virulent Marek's disease virus field strain in China. Poult Sci 2016; 95:1521-1528. [PMID: 26976907 DOI: 10.3382/ps/pew073] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/14/2016] [Indexed: 11/20/2022] Open
Abstract
Marek's disease (MD) has become increasingly common in China, resulting in considerable economic loss. The etiological agent is unclear. In this study, we isolated a field MD virus (MDV) strain, designated SX1301, from CVI988/Rispens-vaccinated chickens with tumors. Co-infection of avian leukosis virus, reticuloendotheliosis virus, and chicken infectious anemia virus was excluded by polymerase chain reaction, enzyme-linked immunosorbant assay, DNA blotting hybridization, and indirect immunofluorescence assay. As with most strains isolated in China, SX1301 had the same amino acid mutation of meq protein at positions 77(E), 80(Y), and 115(A) Animal experimental results showed development of lethal MD in 57% and MD tumor in 23% of the specific pathogen-free chickens inoculated with SX1301, with tumors mainly distributed in spleen, liver, and kidney. CVI988/Rispens protected 83% of chickens upon challenge with SX1301, with a mortality rate and tumor incidence of 10% and 7%, respectively. These results implicated SX1301 as a virulent MDV strain, with commercial MDV vaccine CVI988/Rispens unable to confer adequate protection against SX1301. There have been no reports of very virulent (vv) plus MDV in China, but frequently occurring virulent MDV may account for the repeated outbreaks of MD. Vaccines with greater efficacy are needed to protect against MDV.
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Affiliation(s)
- Ning Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Shuai Su
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China.
| | - Peng Sun
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Yankun Zhang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Ni Han
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Zhizhong Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
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12
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Su S, Cui N, Li J, Sun P, Li H, Li Y, Cui Z. Deletion of the BAC sequences from recombinant meq-null Marek's disease (MD) virus increases immunosuppression while maintaining protective efficacy against MD. Poult Sci 2016; 95:1504-1512. [PMID: 26957626 DOI: 10.3382/ps/pew067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 12/28/2015] [Indexed: 11/20/2022] Open
Abstract
Marek's disease virus (MDV) GX0101 is a field strain of MDV with a naturally occurring insertion of the reticuloendotheliosis virus (REV) long terminal repeat (LTR) fragment. Both copies of the meq gene were knocked out in the GX0101 bacterial artificial chromosome (BAC) clone to construct the recombinant virus SC9-1, resulting in a complete lack of pathogenicity and providing better protection against MD than CVI988/Rispens. In the present study, the BAC sequences in SC9-1 were removed using a cre-loxP system, and the virus termed SC9-2. SC9-2 showed a significant increase in replication in vitro and in vivo. There was a significant decrease in chicken weight, immune organ index, and antibody levels compared with those of SC9-1-inoculated chickens. The immune protection index of SC9-2 was similar to that of SC9-1, and the difference was not significant. The results of our studies demonstrate that the SC9-2 virus provides protection in specific pathogen free (SPF) chickens when challenged with a very virulent MDV rMd5, but it induces immunosuppressive effects in SPF chickens.
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Affiliation(s)
- S Su
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - N Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - J Li
- Tengzhou Animal Husbandry and Veterinary Bureau, Tengzhou, Shandong, 277500, China
| | - P Sun
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - H Li
- Institute of Animal Husbandry and Veterinary Science, Shanghai Academy of Agricultural Sciences, Shanghai, 201106, China
| | - Y Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Z Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, 271018, China.
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