Isolation, identification, and whole genome sequencing of reticuloendotheliosis virus from a vaccine against Marek's disease.
According to the requirements of the Ministry of Agriculture of China, all vaccines must be screened for exogenous virus contamination before commercialization. A freeze-dried vaccine against Marek's disease was used to inoculate specific pathogen-free chickens, from which serum samples were collected after 42 days. The results were positive for reticuloendotheliosis virus antibody, which was indicative of reticuloendotheliosis virus contamination. After neutralization with serum positive for Marek's disease virus, chicken embryo fibroblasts were inoculated with the vaccine. Afterward, viral isolation and identification were performed. One reticuloendotheliosis virus strain (MD-2) was isolated and verified using an immunofluorescence assay. Polymerase chain reaction amplification of the provirus MD-2 genome was performed using seven overlapping fragments as primers. The amplified products were sequenced and spliced to obtain the whole MD-2 genome sequence. The full genome length of MD-2 was 8,284 bp, which had an identity greater than 99% with the prairie chicken isolate APC-566 from the US, the goose-derived isolate 3410/06 from Taiwan, and the chicken-derived reticuloendotheliosis virus isolate HLJR0901 from Heilongjiang Province, China. The MD-2 was phylogenetically close to these isolates. The identity with REV isolate HA9901 from Jiangsu Province of China was 96.7%. The MD-2 had the lowest identity with duck-derived Sin Nombre virus from the United States, with the value of only 93.5%. The main difference lay in the U3 region of the long terminal repeat. The present research indicated that some vaccines produced during specific periods in China might be contaminated by reticuloendotheliosis virus. The reticuloendotheliosis virus strain isolated from the vaccine was phylogenetically close to the prevalent strain, with only minor variations.
Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100094, China China Institute of Veterinary Drug Control, Beijing, 100081, China.
Junping
J
Li
College of Veterinary Medicine, Shandong Agricultural University, Tai'an, 271018, China.
Xuan
X
Dong
China Institute of Veterinary Drug Control, Beijing, 100081, China.
Chenghuai
C
Yang
China Institute of Veterinary Drug Control, Beijing, 100081, China.
Qihong
Q
Li
College of Veterinary Medicine, Shandong Agricultural University, Tai'an, 271018, China.
Zhizhong
Z
Cui
College of Veterinary Medicine, Shandong Agricultural University, Tai'an, 271018, China.
Shuang
S
Chang
College of Veterinary Medicine, Shandong Agricultural University, Tai'an, 271018, China zhaopeng@sdau.edu.cn yukangzhen@yahoo.com.cn yanghanchun1@cau.edu.cn.
Peng
P
Zhao
Ministry of Agriculture, Beijing, 100125, China zhaopeng@sdau.edu.cn yukangzhen@yahoo.com.cn yanghanchun1@cau.edu.cn.
Kangzhen
K
Yu
Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100094, China zhaopeng@sdau.edu.cn yukangzhen@yahoo.com.cn yanghanchun1@cau.edu.cn.
Hanchun
H
Yang
D000818:Animals; D002645:Chickens; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D016679:Genome, Viral; D008380:Marek Disease / Q000517:prevention & control; D022501:Marek Disease Vaccines / Q000032:analysis*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000517:prevention & control; D011533:Proviruses / Q000235:genetics*; D001356:Reticuloendotheliosis virus / Q000235:genetics*; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013047:Specific Pathogen-Free Organisms
D022501:Marek Disease Vaccines
Marek's disease; reticuloendotheliosis virus; vaccine contamination