| 摘要 |
PROBLEM TO BE SOLVED: To obtain a Newcastle disease virus(NDV) mutant which is phenotypicaly V protein positive, in which a prescribed amount or less of its P-gene derived from mRNAs in infected cells encode V ORF, and which is useful for a live vaccine to protect birds against NDV and so on. SOLUTION: A Newcastle disease virus(NDV) mutant expresses its V protein at a reduced level (NDV V). The mutant is phenotypically V protein positive, and <=6%, preferably <=3%, more preferably 1%, of its P-gene derived from mRNAs in infected cell encode V ORF. The phosphoprotein (P) gene mRNA editing locus UUU UUC CC (genome RNA sense) comprises a mutation to reduce editing. The mutation in the editin locus is a nucleotide substitution. A live vaccine against Newcastle disease in birds comprises the NDV mutant and a pharmaceutically acceptable carrier. |
