| Avian leukosis virus Subgroup J (ALV-J) is a retrovirus that infects meat-type chickens. ALV-J was first reported as a new subgroup of ALV by Payne in 1991. It induced avian myelcytomatosis (ML) in broiler. ALV-J was isolated and identified in 1999 from two broiler breeder farms with suspected lesions and 2 of 25 commercial broiler flocks by Prof. Cui ZhiZHong's laboratory in China. Subsequently, more strains of ALV-J were identified in different lines of broiler.Reticuloendotheliosis(RE) is a pathological syndrome caused by reticuloendotheliosis virus( REV). According to the pathogeny and serology, we know REV distributes worldwidely. REV can cause growth slowly, high death and immunsuppression.Three experiments were conducted. In experiment 1, complete cDNA nucleotide sequence of Chinese field strain NX0101 of avian leucosis virus subgroup J was amplified by polymerase chain reaction(PCR). The entire nucleotide sequence of cDNA NX0101 strain was compared with that ofother the ALV-J strains, HPRS103 and ADOL7501. The result provides direct information about the genomic structure and its possible relationships to the biological functions, and aid in the development of new ALV-J vaccines. Several overlapping pairs of primers were designed according to the cDNA sequence of ALV-J reported in foreign. Using PCR, cDNA fragments of ALV-J/NX0101 strain were acquired from infected NX0101-cells. The cDNA fragments were cloned into the vector PMD18-T and then transformed to competent TG1 cells, positive clones were screened and the plasmids were determined by enzyme digestion. The sequences of positive clones were determined by automated sequencer. In experiment 2, To determine the dynamics of monoclonal antibody in culture supernatant, hybridoma cells of 11B154 specific to reticuloendotheliosis virus (REV) were cultured in the 7% CO2 incubator at 37 C with the average density of 0.65 x 106 cells/ml as the start. The total cells and live cells were counted, and REV-specific antibody titers in the supernatant were determined with indirect fluorescence antibody test (IFA) at 24, 48, 72 and 96 hours after culture. In experiment 3, To imitate the vertical infectious of chicken embryos with reticuloendotheliosis virus ( REV ), we inoculated specific-free ( SPF ) chicken embryo (incubated for 1 and 3 days) with variant doses of REV and then hatch them to day 12. These embryos were used to prepare chicken embryo fibroblasts ( CEF ) for detection of REV by indirect fluorescence (IFA) with specific monoclonal antibody 11B118.In experiment 1,sequence analysis showed that the entire genome of cDNA of NX0101 strain consisted of 7682 nucleotides(nt) and code 2560 amino acids. The nucleotide sequence of NXO 101 strain were compared with those of other ALV-J strains, HPRS103 and ADOL7501. The results revealed that the homology of nucleotide sequences of the 5'LTR; the 5'LTR-U3; the 5'LTR-R; the 5'LTR-U5; the 5'UTR among the three strains (NX0101 and HPRS103,NX0101 andADOL7501, HPRS103 and ADOL7501) was 96.6%, 92.9%, 93.8%; 94.6%, 89.7%, 93.8%; 100%, 100%, 100%; 95.0%, 95.0%,92.5%; 95.8%, 95.0 %, 94.1%.The homology of amino acid of the gag, the p19, the p2, the p10, the p27, the p12, the p15 among the three strains (NX0101 and HPRS103, NX0101 and ADOL7501, HPRS103 andADOL7501) was 94.7%, 94.7%, 99.9%; 96.1%, 92.9%, 94.2%; 100%, 100%, 100%; 96.8%, 98.4 %, 98.4%; 94.1%, 95.0%, 97.1%; 93.3%, 92.1%, 95.5%; 96.0%, 96.0%, 98.4%.The homology of amino acid of the pol, the RT p68, the IN p32 among the three strains (NX0101 and HPRS103, NX0101 and ADOL7501, HPRS103 and ADOL7501) was 97.7%, 97.6%, 98.6%; 97.2%, 97.6%, 99.0%; 98.9%, 97.5%, 98.6%.The homology of amino acid of the env, thegp85, the gp3 7 among the three strains (NX0101 and HPRS103, NX0101 and ADOL7501, HPRS103 andADOL7501) was91.8%, 86.5%, 87.6%; 90.3%, 80.1%, 83.1%; 93.4%, 94.4%, 91.9% oThe homology of nucleotide sequences of the the 3'UTR; 3'-LTR; 3'LTR-U3; 3'LTR-R; 3'LTR-U5 among the three strains (NX0101 and HPRS 103 > NX0101 and ADOL7501, HPRS 1...
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