Novel variant strains of infectious bursal disease virus isolated in China

Fan, Linjin; Wu, Tiantian; Hussain, Altaf; Gao, Yulong; Zeng, Xianying; Wang, Yulong; Gao, Li; Li, Kai; Wang, Yongqiang; Liu, Changjun; Cui, Hongyu; Pan, Qing; Zhang, Yanping; Liu, Yufeng; He, Hongjiang; Qi, Xiaole

doi:10.1016/j.vetmic.2019.01.023

Cited by 79 publications

(101 citation statements)

References 48 publications

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“…However, the inflammatory response of heterophils and plasma cells was not seen in the study. Severe lesions due to vIBDV infection were lymphoid follicle atrophy, connective tissue proliferation, infiltration of macrophages and reduced lymphocyte population in the BF (Fan et al, 2019;Xu et al, 2020). Our findings were similar to those of Sharma et al, (1989), Fan et al (2019), and Xu et al (2020), but histopathological findings from week-to-week were more briefly described in this study.…”

Section: Discussionsupporting

confidence: 91%

“…The vvIBDV causes the most severe lesions. The variant IBDV causes no obvious clinical signs or death, although BF atrophy, thymus atrophy and muscular haemorrhage were occurred in chickens (Fan et al, 2019;Xu et al, 2020) The clinical signs and gross findings for broilers were not severe in our study, presumably because the IBDV strain from this study may be a less pathogenic vIBDV strain.…”

Section: Discussionmentioning

confidence: 47%

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Bursa atrophy at 28 days old caused by variant infectious bursal disease virus has a negative economic impact on broiler farms in Japan

et al. 2020

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Infectious bursal disease (IBD), caused by IBD virus (IBDV), is highly contagious, immunosuppressive and causes a negative economic impact on poultry industry. IBDVvaccinated broiler farms at south Kyushu, Japan had a bursa-to-bodyweight ratio (BB ratio) reduction at 28 days (d) old, followed by high mortality 30 d later. We analysed the influence of the IBDV on atrophy of the bursa of fabricius (BF) and the subsequent mortality after 30 d. Ten broilers were sampled at each timepoint from the farm with high mortality at 21, 25, 28 and 35 d. A second flock from the same farm was sampled at 14, 21, 25, 28, 35 and 42 d. IBDV was detected in BF samples at 25, 28 and 35 d and at 21, 25, 28 and 35 d in the first and second flocks, respectively, using immunohistochemical staining and RT-PCR. IBDV isolates from both flocks were closely related to the China KM523643 strain. Histopathology and TUNEL assay indicated apoptosis, severe lymphoid depletion, vacuoles within follicles, lymphoid follicle atrophy and fibrosis in the BF. We observed 75% of the polyserositis and 10% of the airsacculitis at 30 D in dead broilers. The antigenic variant IBDV infection was appeared to be the main influencing factor on BF atrophy and BB ratio reduction in the broilers. High mortality in the broilers after 30 d could be due to secondary infection. The disease caused by IBDV had a negative economic impact in the farm. RESEARCH HIGHLIGHTS. New variant IBDV caused bursa atrophy and reduced BB ratio in 28-day-old broilers.. After vIBDV had infected broilers, at 21 days old they became immunosuppressed.. High mortality at 30 days old in broilers was due to secondary infection.. New vIBDV has a negative economic impact on broiler farms in Japan.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 47%

Bursa atrophy at 28 days old caused by variant infectious bursal disease virus has a negative economic impact on broiler farms in Japan

et al. 2020

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“…Neutralization tests to detect serum neutralizing antibodies have been described previously [9,42]. Briefly, the serum collected after two weeks of immunization was diluted twice (briefly, 100 µL of serum was mixed with 100 µL of RPMI 1640 culture medium in the first hole, then 100 µL of the mixture was mixed with 100 µL of RPMI 1640 culture medium in the second hole, starting from 1:2 1 to 1:2 12 ), and 100 µL of the diluted serum was mixed with 100 µL of 200 TCID 50 (50% tissue culture infective dose, TCID 50 ) vvIBDV-HLJ0504 or avIBDV-SHG19 and incubated for 1 h at 37 • C in a cell culture incubator.…”

Section: Serological Elisa Antibody Detection and Neutralization Testmentioning

confidence: 99%

“…Hence, IBD has received significant attention from the poultry industry, where chickens are protected by vaccination [1]. However, recent reports have suggested that most of the IBDVs popular in Japan, North America, and China were variant IBDVs, and caused huge economic losses [7][8][9][10][11]. Since conventional commercial vaccines cannot provide complete protection against such variant strains [9,12], there is an urgent need to develop a variant IBDV vaccine.…”

Section: Introductionmentioning

confidence: 99%

Recombinant Lactococcus Expressing a Novel Variant of Infectious Bursal Disease Virus VP2 Protein Can Induce Unique Specific Neutralizing Antibodies in Chickens and Provide Complete Protection

Wang

et al. 2020

Viruses

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Recent reports of infectious bursal disease virus (IBDV) infections in China, Japan, and North America have indicated the presence of variant, and the current conventional IBDV vaccine cannot completely protect against variant IBDV. In this study, we constructed recombinant Lactococcus lactis (r-L. lactis) expressing a novel variant of IBDV VP2 (avVP2) protein along with the Salmonella resistance to complement killing (RCK) protein, and Western blotting analysis confirmed that r-L. lactis successfully expressed avVP2-RCK fusion protein. We immunized chickens with this vaccine and subsequently challenged them with the very virulent IBDV (vvIBDV) and a novel variant wild IBDV (avIBDV) to evaluate the immune effect of the vaccine. The results show that the r-L. lactis-avVP2-RCK-immunized group exhibited a 100% protection rate when challenged with avIBDV and 100% survival rate to vvIBDV. Furthermore, this immunization resulted in the production of unique neutralizing antibodies that cannot be detected by conventional ELISA. These results indicate that r-L. lactis-avVP2-RCK is a promising candidate vaccine against IBDV infections, which can produce unique neutralizing antibodies that cannot be produced by other vaccines and protect against IBDV infection, especially against the variant strain.

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“…A live attenuated vaccine, which induces the humoral antibody response, cell-mediated cytotoxicity, as well as a mucosal immunoglobulin A response, is superior to a traditional inactivated vaccine (41). With the increasing occurrence of variant IBDV strains (42), it is becoming challenging to develop antigen-matched live attenuated vaccines, and the conventional method to identify the natural attenuated strains cannot meet the urgent requirement. The reverse genetic system (RGS), a state-of-the-art tool for the generation of recombinant virus, has been increasingly used for vaccine development.…”

mentioning

confidence: 99%

Rapid Generation of Attenuated Infectious Bursal Disease Virus from Dual-Promoter Plasmids by Reduction of Viral Ribonucleoprotein Activity

Yang

Wang

2020

J Virol

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Infectious bursal disease virus (IBDV) of the Birnaviridae family leads to immunosuppression of young chickens by destroying B cells in the bursa of Fabricius (BFs). Given the increasing number of variant IBDV strains, we urgently require a method to produce attenuated virus for vaccine development. To accomplish this goal, the dual-promoter plasmids in which the RNA polymerase II and RNA polymerase I (Pol I) promoters were placed upstream of the IBDV genomic sequence, which was followed by mouse Pol I terminator and a synthetic polyadenylation signal, were developed for rapid generation of IBDV. This approach did not require trans-supplementation of plasmids for the expression of VP1 and VP3, the main components of IBDV ribonucleoprotein (RNP). Based on the finding in this study that the IBDV RNP activity was partially retained by VP1-FLAG, we successfully rescued the replication-competent IBDV/1FLAG expressing VP1-FLAG. Compared with its parental counterpart, IBDV/1FLAG formed smaller size plaques in cultured cells and induced the same 100% immune protection in vivo. However, neither retarded development nor severe BFs lesion was observed in the IBDV/1FLAG-inoculated chickens. Collectively, this is the first report that viral RNP activity was affected by the addition of an epitope tag on the componential viral proteins. Furthermore, this work demonstrates the rapid generation of attenuated IBDV from dual-promoter plasmids via reducing viral RNP activity by a fused FLAG tag on the C terminus of VP1. This would be a convenient strategy to attenuate epidemic variant IBDV strains for rapid and efficient vaccine development. IMPORTANCE Immunosuppression in chickens as a result of infectious bursal disease virus (IBDV) infection leads to significant economic losses in the poultry industry worldwide every year. Currently, vaccination is still the best way to prevent the prevalence of IBDV. However, with the occurrence of increasing numbers of variant IBDV strains, it is challenging to develop antigen-matched live attenuated vaccine. Here, we first developed a dual-promoter reverse-genetic system for the rapid generation of IBDV. Using this system, the attenuated IBDV/1FLAG expressing VP1-FLAG, which displays the decreased viral RNP activity, was rescued. Moreover, IBDV/1FLAG inoculation induced a similar level of neutralizing antibodies to that of its parental counterpart, protecting chickens against lethal challenge. Our study, for the first time, describes a dual-promoter reverse-genetic approach for the rapid generation of attenuated IBDV while maintaining entire parental antigenicity, suggesting a potential new method to attenuate epidemic variant IBDV strains for vaccine development.

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Novel variant strains of infectious bursal disease virus isolated in China

Cited by 79 publications

References 48 publications

Bursa atrophy at 28 days old caused by variant infectious bursal disease virus has a negative economic impact on broiler farms in Japan

Bursa atrophy at 28 days old caused by variant infectious bursal disease virus has a negative economic impact on broiler farms in Japan

Recombinant Lactococcus Expressing a Novel Variant of Infectious Bursal Disease Virus VP2 Protein Can Induce Unique Specific Neutralizing Antibodies in Chickens and Provide Complete Protection

Rapid Generation of Attenuated Infectious Bursal Disease Virus from Dual-Promoter Plasmids by Reduction of Viral Ribonucleoprotein Activity

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