title: Development and application of SYBR Green I real-time PCR assay for the separate detection of subgroup J Avian leukosis virus and multiplex detection of avian leukosis virus subgroups A and B.
abstract: BACKGROUND
  Subgroup A, B, and J ALVs are the most prevalent avian leukosis virus (ALV). Our study attempted to develop two SYBR Green I-based real-time PCR (RT-PCR) assays for specific detection of ALV subgroup J (ALV-J) and multiplex detection of ALV subgroups A and B (ALV-A/B), respectively.
  
  
  RESULTS
  The two assays showed high specificity for ALV-J and ALV-A/B and the sensitivity of the two assays was at least 100 times higher than that of the routine PCR assay. The minimum virus detection limit of virus culture, routine PCR and real-time PCR for detection of ALV-A strain was 10(3) TCID50 units, 10(2) TCID50 units and fewer than 10 TCID50 units, respectively. In addition, the coefficients of variation for intra- and inter-assay were both less than 5%. Forty clinical plasma samples were evaluated by real-time PCR, routine PCR, and virus culture with positive rates of 80% (32/40), 72.5% (29/40) and 62.5% (25/40), respectively. When the assay for detection of ALV-J was used to quantify the viral load of various organ tissues in chicken inoculated by ALV-J strains CHN06 and NX0101, the results exhibited that ALV-J genes could be detected in all organ tissues examined and the highest copies of ALV-J were mainly in heart and kidney samples at 30 weeks post-infection. Except in lung, the virus copies of CHN06 group were higher than that of NX0101 group in various organ tissues.
  
  
  CONCLUSIONS
  The SYBR Green I-based real-time RT-PCR assay provides a powerful tool for the detection of ALV and study of virus replication and infection.
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, People's Republic of China. daimanman1229@163.com.|Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, Guangzhou, People's Republic of China. daimanman1229@163.com.
authors.forename: Manman
authors.initials: M
authors.lastname: Dai
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou, People's Republic of China. hunanfengmin@163.com.
authors.forename: Min
authors.initials: M
authors.lastname: Feng
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, People's Republic of China. jailart@foxmail.com.|Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, Guangzhou, People's Republic of China. jailart@foxmail.com.
authors.forename: Di
authors.initials: D
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, People's Republic of China. weishengcao@yahoo.com.|Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, Guangzhou, People's Republic of China. weishengcao@yahoo.com.
authors.forename: Weisheng
authors.initials: W
authors.lastname: Cao
authors.affiliation: Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, Guangzhou, People's Republic of China. mliao@scau.edu.cn.
authors.forename: Ming
authors.initials: M
authors.lastname: Liao
mesh_terms: D000818:Animals; D001353:Avian Leukosis / Q000175:diagnosis / Q000821:virology*; D001354:Avian Leukosis Virus / Q000145:classification* / Q000235:genetics; D052160:Benzothiazoles; D002645:Chickens; D003959:Diamines; D005814:Genes, Viral; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods; D009930:Organic Chemicals; D011804:Quinolines; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019562:Viral Load
chemical_list: D052160:Benzothiazoles; D003959:Diamines; D009930:Organic Chemicals; D011804:Quinolines; C098022:SYBR Green I