Isolation of subgroup J avian leukosis virus in Korea.

Sung HW, Kim JH, Reddy S, Fadly A.

National Veterinary Research and Quarantine Service, Ministry of Agriculture & Forestry, 480 Anyang 6-Dong, Anyang 430-016, Korea. sunghw@nvrqs.go.kr

Two subgroup J avian leukosis viruses (ALVs) were isolated from broiler breeder flocks, in which myeloid leukosis had occurred. The isolates could be classified as subgroup J ALV by the positive reaction in polymerase chain reaction (PCR) with primers specific for subgroup J ALV. Two isolates replicated in chicken embryo fibroblast (CEF) cells from the alv6 chicken line in which cells are resistant to subgroup A and E ALVs. In in vitro serum neutralization tests with other subgroup ALVs including ADOL-Hc1, the prototype of subgroup J ALVs isolated in the United States of America, two isolates were partially neutralized by antibody to ADOL-Hc1, indicating that Korean isolates and ADOL-Hc1 may be antigenically related, but not identical. When the PCR was done with a primer pair designed to amplify genes of E element and long terminal repeat of proviral DNA, the PCR product size of one isolate (KOAL-PET) was smaller than that of ADOL-Hc1, suggesting that some sequences in these regions are deleted.