Résumé
During July to November in 2007, several outbreaks of Hemangiomas in Hy-line Brown laying hens were observed in China. The virus that infected these flocks was identified in cultured DF-1 cells by PCR and indirect fluorescent assay (IFA) with ALV-J specific monoclonal antibody JE-9. The gp85 gene of one strain named WS0705 of ALV-J was cloned and expressed. Phylogenetic analysis showed that gp85 amino sequences of WS0705 strain had the highest homology with that of the prototype HPRS-103. The gp85 gene from a constructed plasmid pMD18-T-WS0705gp85 was cloned into baculovirus transfer vector. rBac-WS0705gp85 was obtained by the Bac-to-Bac baculovirus expression system. The rBac-WS0705gp85 protein was analyzed by indirect immunofluor escence assay and Western blot. The results showed that positive green fluorescent was present in Sf9 cells infected with the recombinant virus and a 35 kD band was present in western blot. It is concluded that WS0705 gp85 gene was expressed in Sf9 cells infected with the recombinant virus and the SU protein of WS0705 can bind specifically to JE9 MAb of ALV-J. The expressed protein can be used to detect hemangiomas induced by ALV-J.