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ABSTRACT: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the important pathogens causing serious economic losses to swine industry worldwide. PRRSV is genetically and pathologically heterogenous. PRRSV NT0801 strain was isolated in a pig farm with clinical signs and had high pathogenesis in piglets. But its NSP2 gene did not have 30 amino acids deletion as highly pathogenic JXA1 strain. To elucidate the genetic characteristics of PRRSV NT0801 strain, the full-length genome of NT0801 isolate was sequenced and analyzed. The results showed that the genome of PRRSV NT0801 was 15439bp in length, including 29nt Poly(A) tail. Compared with the highly pathogenic JXA1 strain, it had the nucleotide sequence identity of 96.7%, amino acid sequence homology of 97.2% and 98.5% in GP3 and GP5, respectively. Phylogenetic analysis indicated that NT0801 isolate was located between the traditional strain and the highly pathogenic strain. But no obvious recombination signal was observed, compared with other PRRSV isolates with different virulence. The alignment of amino acid sequence of NT0801 with other PRRSV isolates demonstrated that three out of nine sites, being consistent with the highly pathogenic strain, were different from those in highly pathogenic while same as those in traditional strains and JXA1 vaccine strain. And one out of 9 sites was same as that of JXA1 vaccine strain exclusively, two out of 9 sites were different from all the strains. These results indicated that PRRSV NT0801 strain is closely related to highly pathogenic PRRSV, although there has no 30 amino acids deletions in NSP2 region. The epidemic PRRSV strains variation results from the gene mutation. It should be useful for studying on the virulence genes located in different ORFs of PRRSV in the future.
Bing du xue bao = Chinese journal of virology / [bian ji, Bing du xue bao bian ji wei yuan hui] 11/2011; 27(6):542-8.
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ABSTRACT: Haemophilus parasuis is the etiological agent of Glässer's disease characterized by fibrinous polyserositis, polyarthritis, and meningitis in young pigs. But it is difficult to develop universal serological diagnostic tools and effective vaccines against this disease because of the serovar diversity of the isolates. In this study, enterobacterial repetitive intergenic consensus-polymerase chain reaction, were performed to investigate the gene profile of 111 isolates of H. parasuis from China. And a specific common gene of H. parasuis was cloned and identified as the outer-membrane protein (OMP) P2 gene. Sequencing results of OMP P2 genes of 22 isolates showed that they had high homology and could be divided into 2 genetic types. Moreover, the OMPP2 protein was expressed in Escherichia coli expressing system. And the purified recombinant protein provided partial protection against H. parasuis infection in mice. It suggested the OMP P2 was an immunogenic protein and had great potential to serve as a vaccine and diagnostic antigen.
Research in Veterinary Science 09/2011; 93(2):736-42. · 1.65 Impact Factor
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ABSTRACT: From December 2003 to July 2006, a total of 131 (28.4%) Haemophilus parasuis strains were isolated from 462 cases examined in our diagnostic laboratory. These strains were isolated from clinically diseased pigs, and 50 of them along with 15 reference strains of all known serovars were subjected to PCR-FRLP (restriction fragment length polymorphism) analysis by tbpA gene. The analysis of the 1.9-kb tbpA amplicon using TaqI, AvaI and RsaI endonucleases produced 9 RFLP patterns for the 15 reference strains and 13 patterns for the 50 field isolates. And the first three prevalent genotypes in China were DBN (38%), ABN (18%) and DBP (12%). Meanwhile, co-infection of H. parasuis, PRRSV and PCV2 was examined in the 462 pig herds. It is indicated that 11.5% cases (53), 27.9% cases (129) and 4.8% cases (22) were infected only by H. parasuis, PRRSV and PCV2, respectively; and 19.2% cases (89) and 3.0% cases (14) were co-infected with two or all of the three pathogens, respectively; the rest 33.6% cases (155) were not infected by any of the three pathogens. It is confirmed that H. parasuis existed widely in southeast China with numerous genotypes.
Preventive Veterinary Medicine 08/2009; 91(2-4):274-9. · 2.05 Impact Factor
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ABSTRACT: The M protein gene of porcine reproductive and respiratory syndrome virus amplified by PCR was tandem linked with its GP5 gene in shuttle vector in correct frame, resulting in shuttle vector pShuttle-CMV-M-GP5. The positive clone was identified by PCR and further confirmed by sequencing. The constructed plasmid was linearized with Pme I and co-transformed BJ5183 host bacteria with pAdEasy-1 to produce recombinant adenovirus DNA by homologous recombination. Then the adenovirus DNA was linearized with Pac I and transfected into HEK-293A cells to obtain recombinant adenovirus. The specific expression of target proteins by the recombinant adenovirus was verified by indirect immuno-fluorescence assay (IFA) with monoclonal antibodies against M and GP5.The results showed that the tandem linked M with GP5 could be co-expressed by adenovirus vector. Mice immunized with the constructed recombinant adenovirus induced strong humoral immunity (ELISA antibody and virus neutralizing antibody) and cellular immunity (lymphocyte proliferation and CTL responses). The results showed that the recombinant adenovirus has strong immunogenicity and provided the basis for the further experiments in pigs.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology 08/2006; 22(4):555-60.
