In order to develop a vaccine that can simultaneously prevent infection by infectious bursal disease virus(IBDV)and New-castle disease virus(NDV),the IBDV VP2 gene was inserted between the P gene and the M gene of the NDV LaSota vaccine strain ge-nome,and the recombinant virus LS-IBDV-VP2 was constructed and obtained successfully by using the NDV reverse genetic operating system.Mean death time(MDT),egg infectious dose(EID50)and intracerebral pathogenicity index(ICPI)of 1-day-old chicks inocu-lated with recombinant virus and other biological characteristics were determined,and the 18-day-old SPF chicken embryo was immu-nized,NDV antibody was determined by hemagglutination inhibition test(HI)and IBDV VP2 antibody was determined by indirect en-zyme linked immunosorbent assay(ELISA),and the immune response of recombinant virus was evaluated.The results showed that the EID50 of LS-IBDV-VP2 was 108.5/mL,the MDT was 147 h and the ICPI was 0.The titer of NDV antibody reached the highest at 14 days after hatching,which was not significantly different from that of LaSota vaccine strain(P>0.05),and a higher level of IBDV VP2 antibody was also produced at 14 days after hatching.The results of this study indicate that the recombinant LS-IBDV-VP2 has similar biological characteristics to the LaSota vaccine strain,but its recombinant virus has lower virulence and can effectively induce the body to produce antibodies,which has the potential to be a candidate vaccine strain for the prevention of IBDV and NDV.
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