• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.101-106
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• 1998

The present study attempted to apply polymerase chain reaction (PCR) to develop a rapid differential diagnosis among Marek's disease, reticuloendotheliosis and avian leukosis. The primers chosen to detect Marek's disease virus (MDV) flank the 132bp tandem direct repeat of the MDV genome. The primers selected for reticuloendotheliosis virus (REV) and avian leukosis virus (ALV) are based on proviral long terminal repeats of spleen necrosis virus and Rous-associated virus-2 genomes, respectively. The specific PCR products of MDV, REV and ALV were observed with each primer and the reaction was not cross-reacted among the viruses. MDV-specific DNA was also amplified from the MDV-induced lymphoma (MDCC-MSB1) but not from the REV-induced tumor and ALV-induced lymphoma (LSCC-1104B1). In addition, proviral DNA of REV from REV-induced tumor and proviral DNA of ALV from ALV-induced lymphoma were also amplified by REV-specific and ALV-specific PCRs, respectively. Therefore these three PCR methods may be used to rapidly differentiate among MDV, REV and ALV-associated tumors in diagnosis.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.811-817
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• 1998

Humoral and cellular immune responses are depressed in chickens infected with reticuloendotheliosis virus(REV). The extent of depression is influenced by the age of infection and strain of virus. This study was conducted for investigation of immunosuppressive effects of a Korean isolate of REV. Chickens infected with REV-HI, a Korean isolate, at 1 day old were severely suppressed in the vaccinal immunity against Newcastle disease, infectious bronchitis and infectious bursal disease. But these immunosuppressive effects were not observed in chickens infected with the virus at 2 weeks of age, or contact infected by growing in-contact with inoculated chickens from one day old. The clinical signs following infectious laryngotracheitis(ILT) vaccination in chickens infected with REV-HI at 1 day old were more severe than those of uninfected chickens, and some of REV-infected chickens(21.4%) were died after the vaccination. Mortality following virulent ILT virus infection was increased in REV-HI infected chickens. Effects of REV infection at one day old to susceptibilities to subsequent Chicken anemia agent (CAA) infection were also studied. Chickens were infected with REV-HI at 1 day old and subsequently inoculated CAA at 1, 7, 14 and 28 days old, respectively. Mortalities of the chickens infected with REV-HI and subsequent CAA infection were 100, 100, 40 and 0%, respectively, whereas 23, 8, 0 and 0% of chickens infected with only CAA were died, respectively. These above all results suggest that a Korean isolate of REV may be highly immunosuppressive.

• Korean Journal of Veterinary Service
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• v.43 no.3
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• pp.197-200
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• 2020

This study was performed to determine the seroprevalence of reticuloendotheliosis virus (REV) infection in layer chickens in Gyeonggi province, South Korea. Serum samples were collected from 820 layer chickens on 56 flocks in Gyeonggi province. The samples were tested for specific antibodies against REV using commercial enzyme-linked immunosorbent assay (ELISA). The seroprevalence of REV antibodies in the flocks was 62.50% (95% Confidence interval (CI) 49.33~74.40) and the overall seroprevalence in individual chickens was 39.27% (95% CI 35.97~42.65). The results of the present survey indicate that REV infection is prevalent in layer chickens in Gyeonggi province, South Korea. Therefore, effective measures should be taken to prevent and control REV of layer chickens in this province.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.311-323
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• 2000

Immunosuppressive effects of reticuloendotheliosis virus (REV) infection in chickens were investigated. Primary antibody responses to Newcastle disease virus (strain B1) and sheep red blood cells were significantly low in chickens inoculated with the local isolate 89-74 of REV compared to those of uninfected chickens. In chickens infected with REV strain T or 89-74, blastogenesis of spleen cells and peripheral blood lymphocytes (PBL) to concanavalin A (Con A) was severely suppressed. When specific pathogen free (SPF) chickens were inoculated with the isolate, the suppressive effect was observed up to 7 weeks of age while, in the contact infected chickens, the suppression was absent. Similar suppressive effects were observed in chickens inoculated with REV strain T at 2, 3 and 4 weeks of age. When spleen cells or PBL from uninfected chickens were co-cultured with spleen cells or PBL from chickens infected with REV at 1 day-old or 2 week-old, the blastogenesis of the normal cells was suppressed. The suppressive effect of PBL from REV-infected chickens on normal lymphocytes was abrogated by the treatment with trypsin. However the suppressive activity of the REV-infected PBL was not influenced at removing machrophage from the cell suspension by incubation in plastic petri dishes. In addition to the immunosuppression, chickens infected with the REV isolate showed abnormal feather development (nakanuke), anemia, paralysis and retarded growth. Three out of 11 chickens inoculated with the isolate at day-old died between 6 and 9 weeks of age by bacterial infections.

• Korean Journal of Veterinary Research
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• v.48 no.4
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• pp.451-455
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• 2008

Body weights and blood biochemical values in chickens infected with reticuloendotheliosis virus (REV)-HI, a Korean isolate, were studied. REV-HI causes severe body weight depression in chickens inoculated but not in chicken contact-infected. Body weights of infected chickens in 3, 4, and 5 weeks after infection were 78%, 76% and 65% of those of control respectively. Blood glucose levels in REVinfected chickens were extremely high compared with those in control (226 $\geq$ 21 vs. 814 $\geq$91.3 mg/dl in week 2) during the experiment period. Triglyceride levels in REV-infected chickens were significantly higher in week 2 and 3, whereas in week 4, REV-infected chickens showed significantly lower levels than the control. Blood lipase, amylase and alkaline phosphatase levels of REV-infected chickens in week 2 were significantly higher, whereas cholesterol, magnesium and calcium values in week 4 were significantly lower than the control. Other blood biochemical values such as alkaline aminotransferase, aspartate aminotransferase, and $\gamma$-glutamyltransferase were nonsignificantly different from the control. These above results suggest that weight depression by REV may be related with increase of blood glucose, which indicated that REV-infected chickens could not use blood glucose as energy source.

• Korean Journal of Veterinary Research
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• v.45 no.4
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• pp.569-574
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• 2005

Enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to reticuloendotheliosis virus (REV) at single serum dilution was standardized. REV HI, one of the Korean field isolates, was inoculated into chicken embryo fibroblast (CEF) cells and was harvested from the culture fluids and cells after 10 to 12 days. Viruses were purified by centrifugation at the $107,000{\times}g$ for 12 hours on 20, 30, 45% (W/V) sucrose gradient. Virus specific fraction was collected and used as ELISA antigen. To standardize ELISA, the optimal concentration of coating antigen ($1{\mu}g/well$) and conjugate (1/1000) was determined by corrected OD (OD value of positive serum-OD value of negative serum) and P/N ratio (OD value of positive serum/OD value of negative serum). To calculate ELISA titer by measuring absorbance at 1/400 single serum dilution, serum titrations were carried out for various sample sera together with standard positive and negative sera. The observed titers of serum samples were plotted against sample/positive (s/p) ratios at 1/400 serum dilution. From the above data, the ELISA titers could be calculated by the equation of $log_{10}$ ELISA titer = 2.2763 ($log_{10}$ s/p) + 3.482 (r = 0.93). For evaluating the sensitivity, the standardized method were compared with conventional agar gel immunodiffusion (AGID) test method using serum samples collected from REV infected field chicken flocks. Fifty seven of 60 samples (95%) were positive for REV by ELISA, whereas only 11 (18.3%) samples were positive by AGID test. This results suggested that the ELISA tests developed in this study could be used for detection of antibodies to REV with high sensitivity.

• Journal of Veterinary Science
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• v.21 no.3
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• pp.49.1-49.14
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• 2020

Background: Coinfection with avian leukosis virus subgroup J (ALV-J) and reticuloendotheliosis virus (REV) is common in chickens, and the molecular mechanism of the synergistic pathogenic effects of the coinfection is not clear. Exosomes have been identified as new players in the pathogenesis of retroviruses. The different functions of exosomes depend on their cargo components. Objectives: The aim of this study was to investigate the function of co-regulation differentially expressed proteins in exosomes on coinfection of ALV-J and REV. Methods: Here, viral replication in CEF cells infected with ALV-J, REV or both was detected by immunofluorescence microscopy. Then, we analyzed the exosomes isolated from supernatants of chicken embryo fibroblast (CEF) cells single infected and coinfected with ALV-J and REV by mass spectrometry. KEGG pathway enrichment analyzed the co-regulation differentially expressed proteins in exosomes. Next, we silenced and overexpressed tripartite motif containing 62 (TRIM62) to evaluate the effects of TRIM62 on viral replication and the expression levels of NCK-association proteins 1 (NCKAP1) and actin-related 2/3 complex subunit 5 (ARPC5) determined by quantitative reverse transcription polymerase chain reaction. Results: The results showed that coinfection of ALV-J and REV promoted the replication of each other. Thirty proteins, including TRIM62, NCK-association proteins 1 (NCKAP1, also known as Nap125), and Arp2/3-5, ARPC5, were identified. NCKAP1 and ARPC5 were involved in the actin cytoskeleton pathway. TRIM62 negatively regulated viral replication and that the inhibition of REV was more significant than that on ALV-J in CEF cells coinfected with TRIM62. In addition, TRIM62 decreased the expression of NCKAP1 and increased the expression of ARPC5 in coinfected CEF cells. Conclusions: Collectively, our results indicated that coinfection with ALV-J and REV competitively promoted each other's replication, the actin cytoskeleton played an important role in the coinfection mechanism, and TRIM62 regulated the actin cytoskeleton.