Xian-Zhu Xia

Academy of Military Medical Sciences, T’ien-ching-shih, Tianjin Shi, China

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Publications (23)36.44 Total impact

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    ABSTRACT: Rabies is a viral infection of the CNS that is almost always fatal once symptoms occur. No effective treatment of the disease is available and novel antiviral strategies are urgently required. Street rabies viruses are field isolates known to be highly neurotropic. Aptamers are single-stranded oligonucleotides that bind their targets with high affinity and specificity and thus have potential for use in diagnostic and therapeutic applications. In this study, we demonstrate that the aptamers FO24 and FO21, which target RABV-infected cells, can significantly protect mice from a lethal dose of the street rabies virus FJ strain in vivo. Groups receiving preexposure prophylaxis had higher survival rates than the groups receiving postexposure prophylaxis. When mice were inoculated with aptamers (4nmol) for 24h by intracranial or intramuscular injection prior to intramuscular inoculation with the FJ strain, approximately 60% of the mice survived. These results indicate that the FO21 and FO24 aptamers may be used to develop preventative antiviral therapy against rabies disease.
    International immunopharmacology 04/2014; · 2.21 Impact Factor
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    ABSTRACT: The rabies virus (RABV) G protein is the primary contributor to the pathogenicity and protective immunity of RABV. In this study, we generated a recombinant rCVS-11-G strain containing two copies of the G protein derived from the pathogenic wild-type (wt) CVS-11 strain and based on its infectious clone. Compared with the wtCVS-11 strain, the rCVS-11-G strain possessed a larger virion and 1.4-fold more G protein, but it exhibited a similar growth property to the rCVS-11 strain, including passaging stability in vitro. qPCR results showed that the two G genes were over-expressed in BHK-21 cells infected with the rCVS-11-G strain. However, the rCVS-11-G strain presented an 80 % lower LD50 than the wtCVS-11 strain when intracranially (i.c.) inoculated in adult mice. Adult mice that were either intracranially (i.c.) or intramuscularly (i.m.) inoculated with rCVS-11-G strain developed more acute neurological symptoms and greater mortality than those inoculated with the wtCVS-11 strain. Furthermore, the rCVS-11-G strain was more easily and rapidly taken up by neuroblastoma cells. These data indicated that the rCVS-11-G strain might have increased neurotropism because of the over-expression of the pathogenic G protein. The inactivated rCVS-11-G strain induced significantly higher levels of virus neutralization antibodies and provided better protection from street rabies virus challenge in mice. Therefore, the rCVS-11-G strain may be a promising inactivated vaccine strain due to its better immunogenicity.
    Virus Genes 02/2014; · 1.77 Impact Factor
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    ABSTRACT: Rabies is a fatal central nervous system (CNS) disease caused by the neurotropic rabies virus (RABV). The therapeutic management of RABV infections is still problematic, and novel antiviral strategies are urgently required. We established the RVG-BHK-21 cell line, which expresses RABV glycoprotein on the cell surface, to select aptamers. Through 28 iterative rounds of selection, single-stranded DNA (ssDNA) aptamers were generated by exponential enrichment (SELEX). A virus titer assay and a real-time quantitative reverse transcription PCR (qRT-PCR) assay revealed that four aptamers could inhibit the replication of RABV in cultured baby hamster kidney (BHK)-21 cells. However, the aptamers did not inhibit the replication of other virus, e.g., canine distemper virus (CDV) and canine parvovirus (CPV). In addition, the GE54 aptamer was found to effectively protect mice against lethal RABV challenge. After inoculation with aptamers for 24h or 48h, followed by inoculation with CVS-11, approximately 25% to 33% of the mice survived. In summary, we selected aptamers that could significantly protect from a lethal dose of RABV in vitro and in vivo.
    Virus Research 01/2014; · 2.75 Impact Factor
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    ABSTRACT: The VP2 structural protein of parvovirus can produce virus-like particles (VLPs) by a self-assembly process in vitro, making VLPs attractive vaccine candidates. In this study, the VP2 protein of canine parvovirus (CPV) was expressed using a baculovirus expression system and assembled into parvovirus-like particles in insect cells and pupae. Electron micrographs of VLPs showed that they were very similar in size and morphology when compared to the wild-type parvovirus. The immunogenicity of the VLPs was investigated in mice and dogs. Mice immunized intramuscularly with purified VLPs, in the absence of an adjuvant, elicited CD4(+) and CD8(+) T cell responses and were able to elicit a neutralizing antibody response against CPV, while the oral administration of raw homogenates containing VLPs to the dogs resulted in a systemic immune response and long-lasting immunity. These results demonstrate that the CPV-VLPs stimulate both cellular and humoral immune responses, and so CPV-VLPs may be a promising candidate vaccine for the prevention of CPV-associated disease.
    PLoS ONE 01/2014; 9(1):e79575. · 3.53 Impact Factor
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    ABSTRACT: Gene therapy targeting the brain holds great promise in curing nervous system degenerative diseases in clinical applications. With this in mind, in a previous study a 29 amino-acid peptide derived from the rabies virus glycoprotein (RVG29) with a nonamer stretch of arginine residues (RVG29-9R) at its carboxy-terminus was exploited as a ligand for brain-targeting gene delivery. Importantly, the report demonstrated that the RVG29-9R vector was able to cross the blood-brain barrier. RVG29-9R is currently synthesized by commercial companies with high associated costs. In this study, in order to reduce the costs of producing RVG29-9R, we have expressed and purified 6 mg of a recombinant peptide (RVG29-9R-6His) from 0.4 g of cultured Escherichia coli. We assessed the physiochemical properties of RVG29-9R-6His, its cytotoxicity, and the in vitro transfection efficiency in Neuro 2a cells (which express the acetylcholine receptor). Our results reveal that the RVG29-9R-6His peptide recognized Neuro 2a cells in a dose-dependent manner and it was also able to bind plasmid DNA and deliver it into the Neuro 2a cells effectively. Therefore, our study has demonstrated that the recombinant RVG29-9R-6His peptide retains the functions of RVG29-9R and so may provide an economically viable and alternative production method for the manufacture of RVG29-9R.
    Protein Expression and Purification 01/2014; · 1.43 Impact Factor
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    ABSTRACT: To investigate the potential of adeno-associated viruses serotype 2 (AAV2)-mediated RNA interference (RNAi) as antiviral agent against rabies, a recombinant AAV2 vectors expressing siRNA targeting nucleoprotein (N) gene of rabies virus (RABV) (rAAV-N796) were constructed and evaluated. When NA cells pretreated with rAAV-N796 were challenged with RABV, there was 37.8 ± 3.4 to 55.1 ± 5.3% reduction in RABV virus titer. When cells pre-challenged with RABV were treated with rAAV-N796, there was 4.4 ± 1.4 to 28.8 ± 3.2% reduction in RABV virus titer. Relative quantification of RABV transcripts using real-time PCR and western blot revealed that the knockdown of RABV-N gene transcripts was based on the rAAV-N796 inoculation titer. Whatever NA cells was treated with rAAV-N796 before or after challenged with RABV, significant reduction was observed in both administrations. When mice treated intracerebrally with rAAV-N796 were challenged intracerebrally or intramuscally with lethal RABV, there was 50 ± 5.3 and 62.5 ± 4.7% protection, respectively. When mice treated intramuscally with rAAV-N796 were challenged intramuscally with lethal RABV, there was 37.5 ± 3.7% protection. When mice were intracerebrally and intramuscally with rAAV-N796 after exposed to RABV infection 24 hr later, there was 25 ± 4.1% protection The N gene mRNA level in challenged mice brain from three different administrations was reduced with 55, 68, 32 and 25%, respectively. These results indicated that AAV2 vector-mediated siRNA delivery in vitro in NA cells inhibited RABV multiplication; in vivo inhibited RABV multiplication in mice brain and imparted partial protection against lethal rabies. So it may have a potential to be used as an alternative antiviral approach against rabies.
    Journal of Veterinary Medical Science 06/2013; · 0.88 Impact Factor
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    ABSTRACT: Rabies is an acute fatal encephalitis disease that affects many warm-blooded mammals. The causative agent of the disease is Rabies virus (RABV). Currently, no approved therapy is available once the clinical signs have appeared. Aptamers, oligonucleotide ligands capable of binding a variety of molecular targets with high affinity and specificity, have recently emerged as promising therapeutic agents. In this study, sixteen high-affinity single-stranded DNA (ssDNA) aptamers were generated by cell-SELEX. Viral titer assays revealed aptamers could specifically inhibit the replication of RABV in cells but did not inhibit the replication of canine distemper virus or canine parvovirus. In addition, the FO21 and FO24 aptamers, with and without PEGylation, were found to effectively protect mice against lethal RABV challenge. When mice were inoculated with aptamers for 24 h prior to inoculation with CVS-11, approximately 87.5% of the mice survived. Here, we report aptamers that could significantly protect the mice from a lethal dose of RABV in vitro and in vivo, as demonstrated by the results for survival rate, weight loss and viral titers. These results indicate that FO21 and FO24 aptamers are a promising agent for specific antiviral against RABV infections.
    Virus Research 01/2013; · 2.75 Impact Factor
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    ABSTRACT: Rabies virus (RABV) infection continues to be a global threat to human and animal health, yet no curative therapy has been developed. RNA interference (RNAi) therapy, which silences expression of specific target genes, represents a promising approach for treating viral infections in mammalian hosts. We designed six small interfering (si)RNAs (N473, N580, N783, N796, N799 and N1227) that target the conserved region of the RABV challenge virus standard (CVS)-11 strain nucleoprotein (N) gene. Using a plasmid-based transient expression model, we demonstrated that N796, N580 and N799 were capable of significantly inhibiting viral replication in vitro and in vivo. These three siRNAs effectively suppressed RABV expression in infected baby hamster kidney-21 (BHK-21) cells, as evidenced by direct immunofluorescence assay, viral titer measurements, real-time PCR, and Western blotting. In addition, liposome-mediated siRNA expression plasmid delivery to RABV-infected mice significantly increased survival, compared to a non-liposome-mediated delivery method. Collectively, our results showed that the three siRNAs, N796, N580 and N799, targeting the N gene could potently inhibit RABV CVS-11 reproduction. These siRNAs have the potential to be developed into new and effective prophylactic anti-RABV drugs.
    Virus Research 08/2012; 169(1):169-74. · 2.75 Impact Factor
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    ABSTRACT: Aptamers, functional nucleic acids, capable of binding a variety of molecular targets with high affinity and specificity, have emerged as promising therapeutic agents. In this study, the cell surface-systematic evolution of ligands by exponential enrichment (Cell-SELEX) strategy was used to generate DNA aptamers which targeted to the intact rabies virus-infected live cells. Through 35 iterative rounds of selection, five high-affinity single-stranded DNA (ssDNA) aptamers were generated by cell-SELEX. Virus titer assay and real-time quantitative reverse transcription PCR (qRT-PCR) assay revealed that all five aptamers could inhibit replication of rabies virus (RABV) in cultured baby hamster kidney (BHK)-21 cells; and T14 and F34 aptamers were most effective. The qRT-PCR also showed a dose-dependent inhibitory effect in BHK-21 cells. Collectively, these data show the feasibility of generating functionally effective aptamers against rabies virus-infected cells by the Cell-SELEX iterative procedure. These aptamers may prove clinically useful as therapeutic molecules with specific antiviral potential against RABV infections.
    International immunopharmacology 07/2012; 14(3):341-7. · 2.21 Impact Factor
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    ABSTRACT: The H5N1 avian influenza virus (AIV) causes widespread infections in bird and human respiratory tracts, and vaccines and drug therapy are limited in their effectiveness. Recent studies of AIV structures have been published and provide new targets for designing antiviral drugs such as antisense oligonucleotides (AS ODNs), which effectively inhibit gene replication. In this study, we designed and synthesized three AS ODNs (NP267, NP628, NP749) that were specific for the RNA binding region of nucleoprotein (NP) based on AIV structure. Results showed that all three AS ODNs could inhibit viral replication in MDCK cells. The NP628 showed the best antiviral effect of all through viral titers, quantitative RT-PCR and indirect immunofluorescence (IFA) assays. In addition, the liposome mediated NP628 could partially protect the mice from a lethal H5N1 influenza virus challenge. Moreover, the NP628 group had a lower viral titer and lung index in the infected mice when compared with the viral control. Our results showed that AS ODN targeting of the AIV NP gene could potently inhibit AIV H5N1 reproduction, thus, formulating a candidate for an emergent therapeutic drug for the pathogenic H5N1 influenza virus infection.
    International immunopharmacology 09/2011; 11(12):2057-61. · 2.21 Impact Factor
  • Bing du xue bao = Chinese journal of virology / [bian ji, Bing du xue bao bian ji wei yuan hui] 09/2011; 27(5):475-80.
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    ABSTRACT: The capsid structural protein VP2 of canine parvovirus (CPV) can self-assemble into highly organized virus-like particles (VLPs) and retain major immunoreactivity. In this study, different recombinant baculoviruses that expressed varying fusion proteins of the CPV VP2 protein with the T cell determinant and/or the linear virus-neutralizing epitope of rabies virus (RV) were generated. Infection with these baculoviruses changed BmN cell morphology and inhibited their proliferation as well as damaged silkworms and pupae. However, infection with these baculoviruses induced high levels of recombinant protein expression in silkworms and pupae. More importantly, these fusion proteins self-assembled VLPs with properties similar to CPV virions and retained their VP2-specific immunoreactivity, but some retained their RV-specific immunoreactivity. Interestingly, only one fusion protein, T-VP2, maintained its haemagglutination activity. These data indicated that these insertions and replacements in the loop 2 of VP2 did not interfere with the formation of VLP, and silkworms and pupae could act as a low-costing bioreactor for the production of heterologous proteins. Therefore, our findings may provide a new framework for the development of subunit vaccines against RV and CPV.
    Veterinary Microbiology 07/2011; 154(1-2):49-57. · 3.13 Impact Factor
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    ABSTRACT: H5N1 avian influenza virus (AIV) causes widespread infections in poultry and wild birds, and has the potential to emerge as a pandemic threat to human. Antisense oligonucleotides (AS ODNs) are highly effective at inhibiting gene replication. Antibody-mediated delivery is a novel approach to target specific cells and tissues. In this study, we designed and synthesized three AS ODNs (PA4, PA492 and PA1203) specific for conserved region of AIV PA protein, and all the three AS ODNs could inhibit viral replication. The PA492 ODN showed the best antiviral effect by viral titers and quantitative RT-PCR in MDCK cells. The fusion protein scFv-tP was constructed as a single chain variable fragment (scFv) against AIV hemaglutinin antigen with a truncated protamine (tP). The results showed that scFv-tP fusion improved the antiviral effectiveness of PA492 in MDCK cells as measured by viral titers, quantitative RT-PCR and indirect immunofluorescence (IFA) assays. In addition, scFv-tP-delivered PA492 was also found to partially protect mice from lethal H5N1 influenza virus challenge. Using scFv-tP delivery, fluorescein isothiocyanate labeled-PA492 was found to be significantly localized in the lungs, compared to liposome-delivered PA492. Moreover, the fusion protein mediated PA492 had a lower lung index and viral titers in the infected mice as compared with the liposome method. These results provided a potential method for using anti-HA fusion protein for the targeted delivery of AS ODNs against AIV H5N1.
    Vaccine 02/2011; 29(8):1558-64. · 3.77 Impact Factor
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    ABSTRACT: The hemagglutinin antigen (HA) of avian influenza virus (AIV) is an immunogen abundant on the surfaces of infected cells, and can be used as a target for specific antibodies to clear viral infection. Protamine has been demonstrated to deliver DNA into cells effectively. Accordingly, a fusion protein of anti-HA single-chain fragment variable (scFv) and truncated protamine (tP) may be used as a vehicle for delivering the anti-AIV siRNA into the AIV-infected cells for gene therapy. To test this hypothesis, we constructed a novel recombinant plasmid, pET28-scFv-tP, by connecting the genes for anti-H5N1 AIV HA-specific scFv with synthesized oligonucleotides encoding the 22 amino acids of human tP and a linker. Furthermore, the recombinant scFV-tP was expressed and purified, with a yield of 7-8mg of scFv-tP and a purity of >92% from 1L of bacterial culture. Characterization of its bioactivity revealed that scFv-tP recognized HA, similar to its scFv control, in a dose-dependent manner and that the scFv-tP, but not its scFv control, bound to DNA and delivered plasmid and oligonucleotide DNA into the AIV-infected MDCK cells effectively. More importantly, transfection with the mixture of the scFv-tP and plasmid for the NP-specific siRNA significantly inhibited the replication of AIV in MDCK cells, as compared with that transfection with the scFv-plasmid mixture, even with the plasmid in liposome. Our data demonstrated that the recombinant scFv-tP retained the functions of both scFv and tP, and might be potentially used for delivering genetic materials for targeting therapy of AIV infection in vivo.
    Vaccine 04/2010; 28(23):3949-55. · 3.77 Impact Factor
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    ABSTRACT: Two giant pandas (Ailuropoda melanoleuca) died of unknown causes in a Chinese zoo. The clinical disease profile suggested that the pandas may have suffered a viral infection. Therefore, a series of detection including virus isolation, electron microscopy, cytobiological assay, serum neutralization and RT-PCR were used to identify the virus. It was determined that the isolated virus was a canine coronavirus (CCV), on the basis of coronavirus, neutralization by canine anti-CCV serum, and 84.3% to 100% amino acid sequence similarity with CCV. The results suggest that the affected pandas had been infected with CCV.
    Journal of veterinary science (Suwŏn-si, Korea) 10/2009; 10(3):261-3. · 0.89 Impact Factor
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    ABSTRACT: RNA interference is a form of post-transcriptional gene silencing mediated by small interfering RNAs (siRNAs), and it provides a powerful new means to specifically inhibit viral infection. In this study, three siRNAs (ps-PA496, ps-PA1116, and ps-PA1473) targeting the polymerase A (PA) gene of highly pathogenic avian influenza virus (HPAIV) H5N1 were designed and evaluated for their abilities to inhibit HPAIV replication. Results in vitro showed that the viral replication in the siRNAs-treated cells was 78-fold lower than that of the control for ps-PA496. Real-time PCR and indirect immunofluorescence assay also showed a significant reduction of the viral RNA level and protein expression. In vivo results showed a significant decrease of lung virus titers and an increase in the survival rate of infected mice pretreated with ps-PA496. These findings suggested that siRNAs targeting PA could efficiently inhibit HPAIV replication and these conserved regions might become potential therapeutic targets against influenza virus infection.
    Biochemical and Biophysical Research Communications 09/2009; 390(3):421-6. · 2.41 Impact Factor
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    ABSTRACT: To construct Fv antibodies against H5N1 Avian influenza virus hemagglutinin,extracted mRNA from B lymphoblastoid cell lines secreting anti-HA antibodies was used and the VH and VL genes were amplified by RT-PCR and linked together by splicing overlap extension (SOE) with (Gly4 Ser)3 linker. The recombinant plasmid was then transformed to E. coli BL21(DE3) and sequence analysis indicated the total length of scFv was 714 bp and the expression of Fv was validated by PAGE and Western blot.
    Bing du xue bao = Chinese journal of virology / [bian ji, Bing du xue bao bian ji wei yuan hui] 02/2009; 25(1):63-7.
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    ABSTRACT: To evaluate emergency prophylactic effects of the avian influenza virus immunized serum on experimentally infected mice. Serum HI antibody titers of 30 mice were detected at day 1 to 19 after being inoculated with 0.2 ml immune serum to estimate half life of immune serum. Ten mice clinical symptom was recorded to estimate the serum security after mice injected 1.5 ml immune serum. Seventy mice were randomly divided into 7 groups according to random number table and inoculated with 0.2 ml, 0.1 ml and 0.05 ml immune serum respectively via intraperitoneal injection on day 8, 4 and 1 prior to challenged with 10 LD(50) influenza virus intranasal. Mice were observed continually for 14 days to calculate the morbidity, mortality, average survival days and compare the lung index and viral titers in lung. Serum HI antibody titers of mice which inoculated with 0.2 ml immune serum maintained 2(6) in 15 days after injection, but drawdown after day 17, the mice injected 1.5 ml immune serum were all alive and none onset. The survival rate of mice which injected 0.2 ml serum on the day 8, 4, 1 before challenge was 80%, 100% and 100%, and the average survival period was 13.1 days, 14.0 days and 14.0 days respectively. The survival rate of mice which injected 0.1 ml and 0.05 ml serum on day 1 before challenge was 100% and 50%, and the average survival days were 14.0 days and 11.7 days respectively. The mice lung index of experimental groups (0.0096 +/- 0.0033 - 0.0145 +/- 0.0060) was smaller than that of viral control group (0.0199 +/- 0.0025), with a statistical significance (P value 0.0022 - 0.0470, < 0.05). The viral titers in lung were significantly decreased by 2 titer as compared to the viral controls. The avian influenza virus immunized serum might contain the emergency prophylactic effects and could be developed as an agent for possible human-avian influenza pandemic.
    Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 12/2008; 42(11):814-7.
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    ABSTRACT: C57BL/6 mice were inoculated intranasally (50 microl) with serial 10-fold dilution of HAB/01 H5N1 virus. Three and five days later, three mice of each group were euthanized. Lung injury was assessed by observation of lung histopathology, virus titers and MCD50 were also measured. Our data showed that H5N1 viral infection in mice resulted in mainly epithelial injury and interstitial pneumonia, featuring significant weight loss, dramatically increased lung wet weight:body weight ratio, inflammatory cellular infiltration, alveolar and interstitial edema, hemorrhage in lungs with high virus titers, and MCD50 was 10(-6.5)/ 0.05 mL. These results suggested that a mouse model of H5N1 viral infection was successfully established which may benefit study of H5N1 avian influenza virus and pathogenic mechanism of host.
    Bing du xue bao = Chinese journal of virology / [bian ji, Bing du xue bao bian ji wei yuan hui] 12/2008; 24(6):472-7.
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    ABSTRACT: In this study, the HPAIV A/Tiger/Harbin/01/2002 (H5N1) used was originated from tigers and propagated in SPF embryonated hen eggs. TCID5, of the virus was 10(-7.36)/0. 05mL on MDCK cell. The cats were inoculated through bronchus route and then, the cats of dead and control were collected for histopathological and immunohistochemistry examination. Meanwhile, the emulsion supernatant fluid of organs and the pharyngeal swab samples of the dead cats were collected for RT-PCR, survived cats and the control cats were tested for the presence of HI antibody by standard method. The results indicated that the damage of lungs from the dead cats were most obvious, the wide range of red consolidation focus emerged on the lobus pulmonis, the fused focus of infection caused injury of lungs. Histology under the microscope revealed diffuse alveolar damage, confluence phlegmasia pathology, infiltration of lymphomonocytes, sackful of infiltration of macrophages and manipulus protein-like effusion in the alveolar. By immunohistochemistry, the positively stained virus particles were found on the epithelial cells of bronchus and alveolus, and also in the endochylema of lymphomonocytes. The specific electophoretic band of 464bp amplified by RT-PCR from samples of pharyngeal swabs, lungs, kidneys, hearts and brains was as same as the theory value. HI antibody titers of the survived cat were 1:32.
    Bing du xue bao = Chinese journal of virology / [bian ji, Bing du xue bao bian ji wei yuan hui] 12/2007; 23(6):477-80.

Publication Stats

41 Citations
36.44 Total Impact Points

Institutions

  • 2007–2014
    • Academy of Military Medical Sciences
      T’ien-ching-shih, Tianjin Shi, China
  • 2013
    • Jilin Agricultural University
      China
  • 2008–2012
    • Jilin University
      • College of Animal Science and Veterinary Medicine
      Jilin, Jilin Sheng, China
  • 2009
    • Changchun University of Science and Technology
      Changchun, Fujian, China