Identification of two novel multiple recombinant avian leukosis viruses in two different lines of layer chicken

Cai, Liming; Shen, Yanwei; Wang, Guihua; Guo, Huijun; Liu, Jianzhu; Cheng, Ziqiang

doi:10.1099/vir.0.054239-0

Cited by 20 publications

(13 citation statements)

References 28 publications

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“…The major source of REV infection in chicken farms in China is contaminated vaccines (Wei et al, 2012), similar to that previously reported in other countries (Fadly et al, 1996;Hertig et al, 1997;Wei et al, 2012). At the same time, the ALV-J infection has been very common among chicken flocks during the last 20 years in China, such as in white meat-type chickens before 2006 (Du et al, 2000;Cui et al, 2003;Zhang et al, 2004) and in layers in 2002 to 2013 (Xu et al, 2004;Guo et al, 2009;Gao et al, 2012;Cai et al, 2013). This virus continues to spread in different Chinese local breeds (Cheng et al, 2005;Cui et al, 2009;Mao et al, 2013) although eradication programmes have been initiated in some breeder farms.…”

Section: Discussionsupporting

confidence: 72%

Synergistic pathogenic effects of co-infection of subgroup J avian leukosis virus and reticuloendotheliosis virus in broiler chickens

et al. 2015

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To study interactions between avian leukosis virus subgroup J (ALV-J) and reticuloendotheliosis virus (REV) and the effects of co-infection on pathogenicity of these viruses, 1-day-old broiler chicks were infected with ALV-J, REV or both ALV-J and REV. The results indicated that co-infection of ALV-J and REV induced more growth retardation and higher mortality rate than ALV-J or REV single infection (P < 0.05). Chickens co-infected with ALV-J and REV also showed more severe immunosuppression than those with a single infection. This was manifested by significantly lower bursa of Fabricius and thymus to body weight ratios and lower antibody responses to Newcastle disease virus and H9-avian influenza virus (P < 0.05). Perihepatitis and pericarditis related to severe infection with Escherichia coli were found in many of the dead birds. E. coli was isolated from each case of perihepatitis and pericarditis. The mortality associated with E. coli infection in the co-infection groups was significantly higher than in the other groups (P < 0.05). Among 516 tested E. coli isolates from 58 dead birds, 12 serotypes of the O-antigen were identified in two experiments. Different serotypes of E. coli strains were even isolated from the same organ of the same bird. Diversification of O-serotypes suggested that perihepatitis and pericarditis associated with E. coli infection was the most frequent secondary infection following the immunosuppression induced by ALV-J and REV co-infection. These results suggested that the co-infection of ALV-J and REV caused more serious synergistic pathogenic effects, growth retardation, immunosuppression, and secondary E. coli infection in broiler chickens.

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Section: Discussionsupporting

confidence: 72%

Synergistic pathogenic effects of co-infection of subgroup J avian leukosis virus and reticuloendotheliosis virus in broiler chickens

et al. 2015

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“…A recent report showed that REV indeed originated from a recombinant retrovirus that circulated in ancestral mammals and was subsequently experimentally introduced into an avian host by contaminant of Plasmodium lophurae [21]. Furthermore, researchers have already identified natural recombinant retroviruses [23]. If recombination is possible, mixed infection of different REV strains might augment the diversity and genome instability of REV.…”

Section: Resultsmentioning

confidence: 97%

Isolation and full-genome sequence of two reticuloendotheliosis virus strains from mixed infections with Marek’s disease virus in China

et al. 2015

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Reticuloendotheliosis virus (REV), classified as a gammaretrovirus, has a variety of hosts, including chickens, ducks, geese, turkeys, and wild birds. REV causes a series of pathological syndromes, especially the immunosuppression of the host, which may lead to an increased susceptibility to other pathogens, thus greatly damaging the poultry industry. Mixed infections of REV and Marek's disease virus (MDV) have been reported in many countries, including China. Previous reports revealed that MDV vaccines were not efficacious, and even less-virulent MDV strains would cause some losses due to mixed infections with REV. Additionally, contaminants in the MDV vaccine might be the main source of REV. In this study, two clinical samples were collected from two flocks of chickens that were diagnosed with MDV. Subsequently, two REV isolates were obtained from the clinical samples. The isolates, named CY1111 and SY1209, were further confirmed through an indirect immunofluorescence assay and electron microscopy. Complete genome sequences of the two REV strains were determined to test the relationship between them and other REV strains. Phylogenetic trees showed that the two REV strains were closely related to most REV strains that were isolated from a variety of hosts. Therefore, REVs might spread freely among these hosts under natural conditions. Additionally, most REV strains in China were in the same clade. The present work offers some information regarding REV in China.

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“…The strong evidence that EAV-HP participated in the recombination of ALV-J strain HPRS-103 was that the EAV-HP env element with a high degree (>97%) of sequence identity to the env gene of the HPRS-103 (Sacco et al, 2000). Two novel multiple recombinant ALV strains isolated in China displayed high identity with the gp85 gene in ALV-C, gp37 gene in ALV-E, and LTR in ALV-J (Cai et al, 2013). Phylogenetic analysis further confirmed that the two ALV strains were recombinant between ALV-J, ALV-E, and ALV-C (Cai et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…It has been well-known that ALV-J caused damage in poultry industry all over the world (Payne and Nair, 2012) and emerged as a result of a recombination event between exogenous ALV and the endogenous retrovirus element designated EAV-HP (Sacco et al, 2000(Sacco et al, , 2004. In recent years, two novel ALV recombined by ALV-C, ALV-E, and ALV-J were identified in different lines of layer chicken in China (Cai et al, 2013). Furthermore, a novel cross-species recombinant retrovirus has been also reported (Henzy et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Endogenous Retrovirus ev21 Dose Not Recombine with ALV-J and Induces the Expression of ISGs in the Host

Feng

Tan²,

Dai

et al. 2016

Front. Cell. Infect. Microbiol.

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Avian leukosis virus subgroup J (ALV-J) infection can cause tumors and immunosuppression. Endogenous viruses integrate into host genomes and can recombine with exogenous avian leukosis virus (ALV). In this study, we analyzed the interaction of endogenous retrovirus 21 (ev21) with the ALV-J in late-feathering Chinese yellow chicken. Two ALV-J strains M180 and K243 were isolated from late-feathering and fast-feathering Chinese yellow chicken flocks, respectively. The env gene of the two strains showed 94.2–94.8% nucleotide identity with reference ALV-J strains. Compared with the env gene and the LTR of ev21 and M180, the nucleotide identity of LTR was 69.7% and env gene was 58.4%, respectively, especially the amino acid identity of env gene as low as 14.2%. Phylogenetic analysis of the nucleotide sequence of the env gene and the 3′LTR showed that M180 was closely related to ALV-J, and was located in a distinct group with ev21 in the phylogenetic tree. Using co-immunoprecipitation (co-IP), we next demonstrate that the envelope protein of ev21 does not interact with the M180 envelope protein. We further show that the envelope protein of ev21 cannot activate ALV-J LTR promoter activity using luciferase-reporter assays. qPCR and western blot analysis revealed that envelope protein of endogenous ev21 can facilitate the expression of PKR at 6h post ALV-J infection (hpi) and facilitate the expression of ISG12 and CH25H at 24 hpi. However, the expression of the env gene of M180 strain was not significantly at 6 and 24 hpi. We conclude that there is no evidence of recombination between endogenous retrovirus ev21 and ALV-J strain M180 in late-feathering Chinese yellow chicken, and envelope protein of ev21 can affect the expression of host ISGs, but appears not to influence the replication of ALV-J strain M180. This is the first report of interaction among the endogenous retrovirus ev21, ALV-J and the late-feathering chicken.

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Identification of two novel multiple recombinant avian leukosis viruses in two different lines of layer chicken

Cited by 20 publications

References 28 publications

Synergistic pathogenic effects of co-infection of subgroup J avian leukosis virus and reticuloendotheliosis virus in broiler chickens

Synergistic pathogenic effects of co-infection of subgroup J avian leukosis virus and reticuloendotheliosis virus in broiler chickens

Isolation and full-genome sequence of two reticuloendotheliosis virus strains from mixed infections with Marek’s disease virus in China

Endogenous Retrovirus ev21 Dose Not Recombine with ALV-J and Induces the Expression of ISGs in the Host

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