The Analysis Of F Gene Of NDV And The Preparation Of Monoclonal Antibody Against N₈₈ Strain

Ten isolates were isolated and identified from clinical cases infected with chicken Newcastle disease virus (NDV) from year 2002 to 2004, they were named YZ,ZJ,FJ,WX,SH,BM,HA,BJ, WG,NT, respectively. Main function segment of fusion gene with the length of 535bp starting from upstreem 47 to downstreem 581 bp for the above 10 isolates were amplified by RT-PCR, the PCR products were cloned into pGEM^r-T vector and further sequenced. A phylogenetic tree based on the sequence analysis of these isolates was drew according to the known sequences of reference NDV strains. The results revealed that eight of ten NDV isolates belong to genotype VII and the other two are regarded as genotype II. Combination of the result with other similar reports, the genotype W NDV was the prevalent in epizootic of NDV in recent years .In order to differentiate antigenity between NDV genotype VII and II, purified antigens from NDV N88 strain (the clonal strain of Lasota ) were used to immunize 8-week old BALB/c mice for monoclonal antibody development. By using the hybridoma technique, immunized BALB/c mice spleen B cells were fused with SP2/0 cell lines. Indirect ELISA method was performed to screen hybridoma cells which produce antibody directed against NDV. Four hybridoma cells secreting monoclonal antibodies (McAb) were obtained . They were named F₁2B₇D₆, G₄E₅E₉, F₁2H₉F₄F₁2C₇. The McAb-mediated ELISA results showed that three (F₁2B₇D₆, F₁2H₉F₄,F₁2C₇.) of four McAb react with NDV genotype I , genotypeIII, genotype VI,genotype VHstains; the only one McAb G4E5E9 reacts with NDVgenotype VUSX,YG strains, but it can't react with NDV genotype I > genotype IIL genotype VI > genotype VnYG97fnYG98. strains...