[The identification and sequence analysis of ALV-J isolated from layers].

Two Avian leukosis viruses of subgroup J (ALV-J) were isolated from layers by inoculating the sample into chicken embryo fibroblast (CEF) cells and by indirect fluorescent assay (IFA) with ALV-J specific monoclonal antibody JE-9. Sequence comparison indicated the gp85 identities were only in the ranges of 83.4%-87.3% compared with five international reference strains and 86.4%-89.6% compared with eight Chinese strains isolated from white meat-type chickens. The gp37 identities were in the range of 91.8-96.4% compared with the five international strains and 93.4-95.9% compared with the eight domestic strains. When compared with the above thirteen strains, two layers isolates were more close to the prototype HPRS-103 and had less deletion in 3'-Ter than those strains. All strains isolated from white meat-type chickens in China had a deletion in the "E" region of 3'-Ter except these two isolates, suggesting these two ALV-J isolates from layers have different evolution origins from other Chinese isolates from white meat-type chickens.