A recombinant field strain of Marek's disease (MD) virus with reticuloendotheliosis virus long terminal repeat insert lacking the meq gene as a vaccine against MD

Su, Shuai; Cui, Ning; Zhou, Yu; Chen, Zimeng; Li, Yanpeng; Ding, Jiabo; Wang, Yixin; Duan, Luntao; Cui, Zhizhong

doi:10.1016/j.vaccine.2014.12.057

Cited by 15 publications

(6 citation statements)

References 33 publications

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“…The viraemia levels in the GX0101 Δ LTR-infected group were significantly lower than that of the GX010 group that contained the REV LTR (Sun et al, 2010). Only after deletion of the meq gene was the natural MDV REV LTR recombinant, GX0101, fully attenuated (Su et al, 2015). Insertion of an REV LTR into the genome of a vaccine strain CVI988 BAC virus, which is fully attenuated, did not alter the pathogenicity; however growth of the recombinant was altered.…”

Section: Discussionmentioning

confidence: 89%

Protective efficacy of a recombinant bacterial artificial chromosome clone of a very virulent Marek’s disease virus containing a reticuloendotheliosis virus long terminal repeat

et al. 2016

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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- 15I × 7 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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Section: Discussionmentioning

confidence: 89%

Protective efficacy of a recombinant bacterial artificial chromosome clone of a very virulent Marek’s disease virus containing a reticuloendotheliosis virus long terminal repeat

et al. 2016

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“…It is well documented that meq deletion viruses give superior protection against highly virulent MDV challenge ( 16 to 18 ). We hypothesized that Md5BAC Δ meq Δ pp38 would retain this protection efficacy.…”

Section: Resultsmentioning

confidence: 99%

“…Deletion of the meq gene in a range of virulent MDV strains completely disabled tumor induction, suggesting a critical role in virus-induced tumorigenesis ( 15 ). Furthermore, the meq deletion virus gives superior protection against challenge with highly virulent MDV strains, making it an excellent vaccine candidate ( 16 to 18 ). However, the meq deletion virus retains the ability to induce lymphoid organ atrophy, reducing its potential as a vaccine ( 19 ).…”

Section: Introductionmentioning

confidence: 99%

Fully Attenuated meq and pp38 Double Gene Deletion Mutant Virus Confers Superior Immunological Protection against Highly Virulent Marek’s Disease Virus Infection

et al. 2022

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“…Nevertheless, in recent years, several strains of MDVs that have naturally integrated LTR in REV have been isolated [10,11,34], suggesting that a recombinant virus containing this sequence may have a certain survival advantage. This finding provides ideas for the development of a new vaccine for MDV [35]. In this study, two LTR sequences were introduced into the classical MDV vaccine strain Rispens to construct a novel rMDV [20].…”

Section: Discussionmentioning

confidence: 99%

Safety and Efficacy Evaluation of Recombinant Marek’s Disease Virus with REV-LTR

Chen¹,

Yang²,

Hu³

et al. 2020

Vaccines

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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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A recombinant field strain of Marek's disease (MD) virus with reticuloendotheliosis virus long terminal repeat insert lacking the meq gene as a vaccine against MD

Cited by 15 publications

References 33 publications

Protective efficacy of a recombinant bacterial artificial chromosome clone of a very virulent Marek’s disease virus containing a reticuloendotheliosis virus long terminal repeat

Protective efficacy of a recombinant bacterial artificial chromosome clone of a very virulent Marek’s disease virus containing a reticuloendotheliosis virus long terminal repeat

Fully Attenuated meq and pp38 Double Gene Deletion Mutant Virus Confers Superior Immunological Protection against Highly Virulent Marek’s Disease Virus Infection

Safety and Efficacy Evaluation of Recombinant Marek’s Disease Virus with REV-LTR

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