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Li Y, Liu Y, Lin Z, Cui S, Chang S, Cui Z, Zhao P, Wang Y. Role of env gene and LTR sequence in the pathogenesis of subgroup K avian leukosis virus. J Gen Virol 2022; 103. [PMID: 35130137 DOI: 10.1099/jgv.0.001719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Avian leukosis virus (ALV) is a retrovirus that induces tumours in infected birds; ALV is divided into different subgroups according to the env gene and cellular tropism. In general, ALV subgroup J (ALV-J) is considered to be the most pathogenic and prevalent subgroup while subgroup K (ALV-K), a newly identified subgroup, only causes mild symptoms. To illuminate the roles of the env viral gene and LTR sequence in pathogenic differences between ALV-J and ALV-K, rescued ALV-J strain rSDAU1005, rescued ALV-K strain rJS11C1, and recombinant strains rENV(J)-LTR(K) and rENV(K)-LTR(J) were characterized and investigated in this study. Among rescued viruses, rSDAU1005 had the highest replication efficiency while rJS11C1 replicated the slowest (replication efficiency rankings were rSDAU1005 >rENV(K)-LTR(J)>rENV(J)-LTR(K)>rJS11 C1). The luciferase reporter gene assay results showed that the promoter activity of ALV-K LTR was lower than that of the ALV-J LTR promoter, which may have accounted for the slower replication efficiency of ALV-K. Pathogenicity of the four rescued viruses was determined via inoculating the yolk sacs of specific-pathogen-free chickens. The results demonstrated that all four viruses were pathogenic; rSDAU1005 caused the most severe growth retardation and immunosuppression. rENV(J)-LTR(K) was more pathogenic when compared to rENV(K)-LTR(J), indicating that env and the LTR sequence play important roles in pathogenicity between ALV-K and ALV-J. Additionally, env seemed to especially play a role in ALV-K pathogenesis. This study provided scientific data and insight to improve detection methods and judgement criteria in ALV clearance and surveillance.
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Affiliation(s)
- Yang Li
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, PR China.,China Animal Health and Epidemiology Center, Qingdao, PR China
| | - Yi Liu
- China Animal Disease Control Centre, Beijing, PR China
| | - Zhanye Lin
- Ministry of Agriculture and Rural Affairs of China, Animal Husbandry and Veterinary Bureau, Beijing, PR China
| | - Shuai Cui
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, PR China
| | - Shuang Chang
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, PR China
| | - Zhizhong Cui
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, PR China
| | - Peng Zhao
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, PR China
| | - Yixin Wang
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, PR China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, PR China
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Ellington C, Cortes AL, Faiz NM, Mays JK, Fadly A, Silva RF, Gimeno IM. Characterization of Md5-BAC-REV-LTR virus as Marek's disease vaccine in commercial meat-type chickens: protection and immunosuppression. Avian Pathol 2021; 50:490-499. [PMID: 34463588 DOI: 10.1080/03079457.2021.1970108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Md5-BAC-REV-LTR is a recombinant Marek's disease virus (MDV), with an insertion of the long terminal repeat (LTR) of reticuloendotheliosis virus (REV) into the genome of the highly virulent MDV strain rMd5. It has been shown that Md5-BAC-REV-LTR does not induce tumours and confers high protection against challenge with MDV in 15 × 7 chickens. The objective of the present study was to evaluate the protection and safety (in terms of oncogenicity and immunosuppression) of Md5-BAC-REV-LTR in commercial meat-type chickens bearing maternal antibodies against MDV. Our results show that sub-cutaneous administration of Md5-BAC-REV-LTR at 1 day of age conferred high protection (protection index PI = 84.2) against an early challenge (1 day) by contact exposure to shedder birds infected with the vv+ MDV 648A strain. In such stringent challenge conditions, Md5-BAC-REV-LTR was more protective than a commercial CVI988 (PI = 12.4) and similar to the experimental vaccine Md5-BACΔmeq (PI = 92.4). Furthermore, Md5-BAC-REV-LTR did not induce either tumours or immunosuppression in this study. Immunosuppression was evaluated by the relative lymphoid organ weights and also by the ability of the vaccine to induce late-MDV-induced immunosuppression associated with reactivation of the virus. This study shows that Md5-BAC-REV-LTR has the potential to be used as a MD vaccine and is highly protective against early challenge with vv+ MDV. RESEARCH HIGHLIGHTSMd5-BAC-REV-LTR is highly protective against early challenge with vv+ MDV in commercial meat-type chickens.Md5-BAC-REV-LTR does not cause early immunosuppression.Md5-BAC-REV-LTR does not cause late immunosuppression.Unlike other serotype 1 vaccines, Md5-BAC-REV-LTR is not detected in feather pulp at 7 days post vaccination.
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Affiliation(s)
- C Ellington
- Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, Raleigh, NC, USA
| | - A L Cortes
- Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, Raleigh, NC, USA
| | - N M Faiz
- Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, Raleigh, NC, USA.,Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Malaysia
| | - J K Mays
- USDA-ARS Avian Disease and Oncology Laboratory, East Lansing, MI, USA
| | - Aly Fadly
- USDA-ARS Avian Disease and Oncology Laboratory, East Lansing, MI, USA
| | - Robert F Silva
- USDA-ARS Avian Disease and Oncology Laboratory, East Lansing, MI, USA
| | - I M Gimeno
- Department of Population Health and Pathobiology, Veterinary School, North Carolina State University, Raleigh, NC, USA
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Cui N, Cui X, Huang Q, Yang S, Su S, Xu C, Li J, Li W, Li C. Isolation and Identification of Subgroup J Avian Leukosis Virus Inducing Multiple Systemic Tumors in Parental Meat-Type Chickens. Front Vet Sci 2021; 7:614854. [PMID: 33585604 PMCID: PMC7873458 DOI: 10.3389/fvets.2020.614854] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/31/2020] [Indexed: 11/28/2022] Open
Abstract
Avian leukosis virus (ALV) continues evolving to obtain new genomic characters to enhance its pathogenicity. In the present study, an ALV-J strain LH20180301 was isolated from broiler breeder chickens that reached the speak of paralyzation before 20-week-old. The necropsy chickens showed subcutaneous and muscular hemorrhage, and developed tumors in multiple organs including bone, liver, spleen, and kidney. The complete provirus was then cloned and sequenced to investigate the molecular characteristics and oncogenicity etiology of this virus associated with the outbreak of disease. The genomic structure of the reported ALV-J strain LH20180301 was highly conservative with other ALVs. Recombination events between the virus with endogenous virus were identified in the viral genome. Compared with the ALV-J original HPRS-103 strain, the major recombination sites of the viral genome with ev-1 were located in 5′ UTR-gag and 3′ UTR regions. Phylogenetic analysis of group specific antigen gp85 encoding protein showed that the LH20180301 branched with ALV-J prevalent in “yellow chickens” of local breeds in South China. Nine amino acids (N58, D60, K70, A71, K108, N112, N113, N121, R272) in the gp85 were highly conserved among ALV-J isolates before 2012, but various mutations were found in the late isolates including LH20180301. In addition, the LH20180301 strain also had the same deletion pattern of 3′ UTR with them. Therefore, LH20180301 might derive from the same ancestor with those viruses and may be the trend of ALV-J evolution in China. The defined new genomic characters in the gp85 and 3′ UTR region of ALV-J might provide the molecular basis for its enhanced oncogenicity.
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Affiliation(s)
- Ning Cui
- Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Xuezhi Cui
- Shandong New Hope Liuhe Group Co., Ltd, Qingdao, China
| | - Qinghua Huang
- Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Shaohua Yang
- Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Shuai Su
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China
| | - Chuantian Xu
- Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Jianhe Li
- Shandong Nongke Animal Husbandry Technology Co., Ltd, Jinan, China
| | - Wenfeng Li
- Jinan Poultry Livestock Assistance Technology Co., Ltd, Jinan, China
| | - Chao Li
- Shandong Nongke Animal Husbandry Technology Co., Ltd, Jinan, China
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Zhou Z, Cui N, Su S, Sun S, Cui Z. The molecular basis for host responses to Marek's disease viruses integrated with different retro-viral long terminal repeat. Poult Sci 2018; 97:3015-3022. [PMID: 29917138 DOI: 10.3382/ps/pey135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 06/13/2018] [Indexed: 12/19/2022] Open
Abstract
Integration of retro-viral long terminal repeat (LTR) into the Marek's disease virus (MDV) genome can occur both in co-cultivation cell cultures and naturally in dual infected chickens. It is clear that the LTR insert is associated with the pathogenicity of MDV. The objective of this study was to compare the host responses to MDV with a different retro-viral LTR insert. Gene-chip containing chicken genome was employed to investigate the gene transcription profile of chicken embryo fibroblasts cells, and 795 genes were differentially expressed in chicken embryo fibroblasts infected with GX0101 with a reticuloendotheliosis virus LTR insert as compared to GX0101-ALV-LTR significantly. The differentially expressed genes were mostly associated with the regulation of transcription and the development of multiple organs. Based on the bio functions of the differential genes, infection of GX0101 was predicated with a greater development disorder of multiple systems, resulting in higher growth retardation, mortality, tumorigenicity, and immunosuppression in chickens than GX0101-ALV-LTR. Collectively, our results provided valuable insights into elucidation of the possible relationship between retro-viral LTR insert and the observed phenotypes caused by MDV recombinant viruses.
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Affiliation(s)
- Zhongwen Zhou
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Ning Cui
- Shandong Key Laboratory of Animal Disease Control & Breeding; Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Shuai Su
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Shuhong Sun
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Zhizhong Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong 271018, China
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