Immunological effects of reticuloendotheliosis virus as potential contaminant of Marek's disease vaccines

Bülow, Vicco von

doi:10.1080/03079457708418247

Cited by 45 publications

(16 citation statements)

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“…Furthermore, REV has been reported to drop the effectiveness of the vaccine against MDV. Bulow [7] showed that antibody titers to Turkey herpesvirus (HVT) in chickens infected simultaneously for 3 days with HVT and REV were very low compared with those in chickens inoculated with [8]. Subsequently, Sun et al [9] demonstrated that the deletion of the LTR of GX0101 decreased its capacity for horizontal transmission.…”

Section: Introductionmentioning

confidence: 96%

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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Section: Introductionmentioning

confidence: 96%

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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“…REV has extensive avian hosts, including chickens, turkeys, ducks, mallards, geese, peafowl, pheasants, pigeons, Hungarian partridges, Chinese partridges, Attwater’s prairie chickens, and many other wild birds [32,33,34,35,36,37,38,39]. REV infection of susceptible hosts, such as chicks, usually causes atrophy of the thymus and bursa of Fabricius, impairing the development and immune system functions of infected hosts, resulting in the suppression of host immune responses to some avian vaccines [40,41,42]. In addition, REV can be present as a contaminant in a variety of poultry biologics and vaccines [43,44,45,46,47,48,49].…”

Section: Introductionmentioning

confidence: 99%

Co-Infection with Marek’s Disease Virus and Reticuloendotheliosis Virus Increases Illness Severity and Reduces Marek’s Disease Vaccine Efficacy

Sun

Zhang

Zhou

et al. 2017

Viruses

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Marek’s disease virus (MDV) and reticuloendotheliosis virus (REV) cause Marek’s disease (MD) and reticuloendotheliosis (RE), respectively. Co-infection with MDV and REV is common in chickens, causing serious losses to the poultry industry. However, experimental studies of such co-infection are lacking. In this study, Chinese field strains of MDV (ZW/15) and REV (JLR1501) were used as challenge viruses to evaluate the pathogenicity of co-infection and the influence of MD vaccination in chickens. Compared to the MDV-challenged group, the mortality and tumor rates increased significantly by 20.0% (76.7 to 96.7%) and 26.7% (53.3 to 80.0%), in the co-challenged group, respectively. The protective index of the MD vaccines CVI988 and 814 decreased by 33.3 (80.0 to 47.7) and 13.3 (90.0 to 76.7), respectively. These results indicated that MDV and REV co-infection significantly increased disease severity and reduced the vaccine efficacy. The MDV genome load showed no difference in the feather pulps and spleen, and pathogenicity-related MDV gene expression (meq, pp38, vIL-8, and ICP4) in the spleen significantly increased at some time points in the co-challenged group. Clearly, synergistic pathogenicity occurred between MDV and REV, and the protective efficacy of existing MD vaccines was attenuated by co-infection with Chinese field MDV and REV strains.

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“…Von Bulow (1977) suggested that, because of the immunodepressive effect of REV on HVT antibody induction, REV contamination of MD vaccine might interfere with the induction of MD immunity.…”

Section: Introductionmentioning

confidence: 99%

Effects of reticuloendotheliosis virus on the response of chickens to infectious laryngotracheitis virus

Motha

1982

Avian Pathology

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SUMMARYEffects of reticuloendotheliosis virus (REV) on the response to infectious laryngotracheitis virus (ILTV) were investigated in young chickens with and without maternally derived antibody (MAb) to REV. In the first experiment a group of 1-day-old chickens without REV MAb were inoculated at 1 day of age with REV whilst another group of similar chickens were left uninoculated. All chickens were vaccinated with ILTV at 7 days of age. There was a significantly higher proportion of infectious laryngotracheitis (ILT) post-vaccinal ophthalmia (p.v.o.) in the group inoculated with REV.In the second experiment chickens with and without MAb to REV were inoculated at 1 day old with REV. These chickens, together with others not inoculated with REV, were vaccinated with ILTV isolate SA-2 8 days later. A virulent ILTV isolate, G, was used to challenge all the chickens 20 days after vaccination. Again the chickens without MAb to REV inoculated with REV showed a higher proportion of ILT p.v.o. and a significantly higher mortality rate due to ILT following vaccination. In the chickens inoculated with REV at 1 day of age and not vaccinated but challenged with ILTV there was a significantly higher mortality and rate of clinical signs due to ILT in those birds without than in those with REV MAb. In both experiments chickens from REV negative parents were found to be free of REV neutralising MAb. However, only 30% of chickens originating from a flock known to be infected with REV had a titre of 1/40 or higher. In spite of this, this group was significantly more resistant than the group without REV MAb to the immunosuppressive effect of inoculation at 1 day old with REV. This was demonstrated by their lower susceptibility (i.e. less p.v.o. and mortality) to the vaccination and challenge with ILTV. Chickens without REV MAb developed neutralising antibodies within 2 weeks of inoculation with REV. Irrespective of the REV MAb status 1-dayold chickens inoculated with REV were viraemic within a week.

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Immunological effects of reticuloendotheliosis virus as potential contaminant of Marek's disease vaccines

Cited by 45 publications

References 12 publications

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

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

Co-Infection with Marek’s Disease Virus and Reticuloendotheliosis Virus Increases Illness Severity and Reduces Marek’s Disease Vaccine Efficacy

Effects of reticuloendotheliosis virus on the response of chickens to infectious laryngotracheitis virus

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