Preparation and Specific Identification of Single Factor Serum of Subgroup K Avian Leukosis Virus gp85

This study was to prepare a diagnostic serum to rapidly diagnose subgroup K avian leukemia virus (ALV-K).The ALV-K were inoculated in DF1 cells and extracted DNA from infected cells to amplify ALV-K-gp85 (1 005 bp) and ALV-K-gp85 (fragment) (510 bp) genes by PCR.Their correct reading frames were inserted into pET-28a(+) expression vector,then transformed into BL21 (Rosetta) strain.The expressed proteins were used to immune Kunming White mice to prepare antiserum.Recombinant fusion proteins of 39.85 and 22.01 ku were successfully obtained and showed good immunogenicity.Indirect immunofluorescence assay (IFA) showed that the two sera could react with ALV-K,but could not react with ALV-A,ALV-B and ALV-J.The experiment prepared the single factor serum that could be used to specifically diagnosis subgroup K avian leukemia for the first time,at the same time,the single factor serum laid the foundation for rapid diagnoses of subgroup K avian leukemia.