Weiqi Pan

Publications (9)25.44 Total impact

• Article: Circumventing antivector immunity by using adenovirus-infected blood cells for repeated application of adenovirus-vectored vaccines: proof of concept in rhesus macaques.

  Caijun Sun, Liqiang Feng, Yinfeng Zhang, Lijun Xiao, Weiqi Pan, Chufang Li, Linqi Zhang, Ling Chen
  [show abstract] [hide abstract]
  ABSTRACT: Adenovirus has been extensively exploited as a vector platform for delivering vaccines. However, preexisting antiadenovirus immunity is the major stumbling block for application of adenovirus-vectored vaccines. In this study, we found that freshly isolated peripheral blood mononuclear cells (PBMCs), mostly CD14(+) cells, from adenovirus serotype 5 (Ad5)-seropositive primates (humans and rhesus macaques) can be efficiently infected with Ad5 in vitro. On the basis of this observation, a novel strategy based on adenoviral vector-infected PBMC (AVIP) immunization was explored to circumvent antivector immunity. Autologous infusion of Ad5-SIVgag-infected PBMCs elicited a strong Gag-specific cellular immune response but induced weaker Ad5-neutralizing antibody (NAb) in Ad5-seronegative macaques than in macaques intramuscularly injected with Ad5-SIVgag. Moreover, Ad5-seropositive macaques receiving multiple AVIP immunizations with Ad5-SIVenv, Ad5-SIVgag, and Ad5-SIVpol vaccines elicited escalated Env-, Gag-, and Pol-specific immune responses after each immunization that were significantly greater than those in macaques intramuscularly injected with these Ad5-SIV vaccines. After challenged intravenously with a highly pathogenic SIVmac239 virus, macaques receiving AVIP immunization demonstrated a significant reduction in viral load at both the peak time and set-point period compared with macaques without Ad5-SIV vaccines. Our study warranted further research and development of the AVIP immunization as a platform for repeated applications of adenovirus-vectored vaccines.
  Journal of Virology 08/2012; 86(20):11031-42. · 5.40 Impact Factor
• Article: Improvement of influenza vaccine strain A/Vietnam/1194/2004 (H5N1) growth with the neuraminidase packaging sequence from A/Puerto Rico/8/34.

  Weiqi Pan, Zhenyuan Dong, Weixu Meng, Wei Zhang, Ting Li, Chufang Li, Beiwu Zhang, Ling Chen
  [show abstract] [hide abstract]
  ABSTRACT: H5N1 influenza candidate vaccine viruses were developed using the "6+2" approach. The hemagglutinin (HA) and neuraminidase (NA) genes were derived from the popular H5N1 virus and the remaining six internal segments were derived from the A/Puerto Rico/8/34 strain (H1N1, PR8). However, some of these candidate strains have been reported to produce relatively low yields in vaccine manufacture. In this study, we found that the NA vRNA of the A/Vietnam/1194/2004 strain (H5N1, VN1194) was poorly packaged into recombinant viruses with a backbone of PR8 genes, which resulted in the formation of defective virions that did not include the NA vRNA in the genome. Using recombinant DNA techniques, we constructed a chimeric NA gene with the coding region of VN1194 NA flanked by the packaging signal sequence of the PR8 NA gene (41 bp form the 3' end of the vRNA and 67 bp from the 5' end). The packaging of the NA vRNA was restored to normal levels in the recombinant viruses containing the chimeric NA gene. Recombinant viruses containing the chimeric NA replicated much better in chicken embryonated eggs than viruses with the wild-type NA from VN1194. These findings suggest a novel strategy to improve in ovo growth of vaccine strains and to increase the number of vaccine doses available to save people if a pandemic were to occur.
  Human vaccines & immunotherapeutics. 02/2012; 8(2):252-9.
• Article: Determination of serum neutralization antibodies against seasonal influenza A strain H3N2 and the emerging strains 2009 H1N1 and avian H5N1.

  Ruiqi Zhang, Xia Rong, Weiqi Pan, Tao Peng
  [show abstract] [hide abstract]
  ABSTRACT: Humoral virus neutralizing activity is crucial in preventing influenza virus infection. However, the influenza neutralizing activity in the general population remains unclear. In this study we performed a serological survey of 200 blood donors from Guangzhou, China. Using a microneutralization (MN) assay, neutralizing activities against influenza A 2009 H1N1, H3N2 and H5N1 were measured. Anti-haemagglutinin antibody was assayed by haemagglutination inhibition (HI) test. Also, antibodies against M1 and M2 matrix proteins were measured using an enzyme-linked immunosorbent assay (ELISA). By MN assay, 86% of the individuals showed neutralizing activity against H3N2, 11% against 2009 H1N1, and none against H5N1. The positive rate for H3N2 increased as the age of individuals increased. Interestingly, males displayed a 4 times higher positive rate against 2009 H1N1 than females. The results of ELISA revealed that 97.5% of the individuals had positive M1 titres and 21% had positive M2 titres. Furthermore, anti-haemagglutinin antibody had a much higher correlation with the neutralization activity than anti-M1 and anti-M2 antibodies. Neutralizing activities against H5N1 and 2009 H1N1 were low in the general population. Therefore, public health agencies should design strategies for preventing potential H5N1 and 2009 H1N1 pandemics.
  Scandinavian Journal of Infectious Diseases 03/2011; 43(3):216-20. · 1.72 Impact Factor
• Article: Epidemiology of adenovirus type 5 neutralizing antibodies in healthy people and AIDS patients in Guangzhou, southern China.

  Caijun Sun, Yinfeng Zhang, Liqiang Feng, Weiqi Pan, Maochao Zhang, Zheyu Hong, Xin Ma, Xiaoping Chen, Ling Chen
  [show abstract] [hide abstract]
  ABSTRACT: Recombinant adenovirus serotype 5 (Ad5) viruses have been extensively explored as vectors for vaccination or gene therapy. However, one major obstacle to their clinical application is the high prevalence of preexisting anti-Ad5 immunity resulting from natural infection. It has been reported that there are geographic variations in the prevalence of natural adenovirus infection. In the present study, we investigated the seroprevalence of Ad5 in Guangzhou, southern China by measuring the Ad5 neutralizing antibodies in blood samples collected from several sites. The seroprevalence was 77.34% in the general healthy population. The seroprevalence and antibody titers increased with age, with the older population (41-72 years old) having the highest seropositivity (84.8%) and percentage (54.4%) of high Ad5 neutralizing antibody titers (>1000). The dynamics of Ad5 neutralizing antibodies were stable and persistent over the course of eight months. Furthermore, the seroprevalence of Ad5 in the HIV-infected AIDS patients was investigated and there was no significant difference from the general healthy population. Our survey provides useful insights for the future development of Ad5-based vaccination and gene therapy.
  Vaccine 03/2011; 29(22):3837-41. · 3.77 Impact Factor
• Source

  Available from: Tao Peng

  Article: Potent neutralization of influenza A virus by a single-domain antibody blocking M2 ion channel protein.

  Guowei Wei, Weixu Meng, Haijiang Guo, Weiqi Pan, Jinsong Liu, Tao Peng, Ling Chen, Chang-You Chen
  [show abstract] [hide abstract]
  ABSTRACT: Influenza A virus poses serious health threat to humans. Neutralizing antibodies against the highly conserved M2 ion channel is thought to offer broad protection against influenza A viruses. Here, we screened synthetic Camel single-domain antibody (VHH) libraries against native M2 ion channel protein. One of the isolated VHHs, M2-7A, specifically bound to M2-expressed cell membrane as well as influenza A virion, inhibited replication of both amantadine-sensitive and resistant influenza A viruses in vitro, and protected mice from a lethal influenza virus challenge. Moreover, M2-7A showed blocking activity for proton influx through M2 ion channel. These pieces of evidence collectively demonstrate for the first time that a neutralizing antibody against M2 with broad specificity is achievable, and M2-7A may have potential for cross protection against a number of variants and subtypes of influenza A viruses.
  PLoS ONE 01/2011; 6(12):e28309. · 4.09 Impact Factor
• Article: Generation of replication-competent recombinant influenza A viruses carrying a reporter gene harbored in the neuraminidase segment.

  Feng Li, Liqiang Feng, Weiqi Pan, Zhenyuan Dong, Chufang Li, Caijun Sun, Ling Chen
  [show abstract] [hide abstract]
  ABSTRACT: Replication-competent influenza viruses carrying reporter genes are of great use for basic research, screening of antiviral drugs, and neutralizing of antibodies. In this study, two recombinant influenza A viruses with a neuraminidase (NA) segment harboring enhanced green fluorescent protein (EGFP) in the background of A/PR/8/34 (PR8) were generated. The viral RNA (vRNA)-specific packaging signals for NA were largely retained for efficient packaging. An "autocleave" 2A peptide sequence, which was inserted at the N terminus or the COOH terminus of NA to link with EGFP, enabled NA and EGFP to be expressed monocistronically. Further analysis demonstrated that both viruses, named rPR8-EGFP+NA and rPR8-NA+EGPF, although with some characteristic differences in growth and EGFP expression, could replicate in noncomplementary cells and propagate to large quantities while maintaining genome stability after multiple passages in embryonated eggs. These replication-competent influenza viruses carrying reporter genes are a great addition to the tool set for developing antiviral therapeutics and vaccines and for in vivo studies of viral dissemination and pathogenicity.
  Journal of Virology 11/2010; 84(22):12075-81. · 5.40 Impact Factor
• Article: Comparative immunogenicity of recombinant adenovirus-vectored vaccines expressing different forms of hemagglutinin (HA) proteins from the H5 serotype of influenza A viruses in mice.

  Xiangjing Hu, Weixu Meng, Zhenyuan Dong, Weiqi Pan, Caijun Sun, Ling Chen
  [show abstract] [hide abstract]
  ABSTRACT: Recent outbreaks of highly pathogenic avian influenza (HPAI) H5N1 viruses in poultry and their subsequent transmission to humans have highlighted an urgent need to develop preventive vaccines in the event of a pandemic. In this paper we constructed recombinant adenovirus (rAd)-vectored influenza vaccines expressing different forms of H5 hemagglutinin (HA) from the A/Vietnam/1194/04 (VN/1194/04) virus, a wild-type HA, a sequence codon-optimized HA and a transmembrane (TM) domain-truncated HA. Compared to the rAd vectors expressing the wild-type HA (rAd-04wtHA) and the TM-truncated form of HA (rAd-04optHA-dTM), the rAd vectored vaccine with the sequence codon-optimized HA (rAd-04optHA) showed a tendency to induce much higher hemagglutinin inhibition (HI) antibody titers in mice immunized with a prime-boost vaccine. Furthermore, administration of the rAd-04optHA vaccine to mice could elicit cross-reactive immune responses against the antigenically distinct HK/482/97 virus. Additionally, we constructed another vector containing the codon-optimized HA of the A/Hong Kong/482/97 (HK/482/97) virus. Administration of a bivalent immunization formulation including the rAd-04optHA and rAd-97optHA vaccines to mice induced a stronger immune response against HK/482/97 virus than the monovalent formulation. Taken together, these findings may have some implications for the development of rAd-vectored vaccines in the event of the pandemic spread of HPAI.
  Virus Research 09/2010; 155(1):156-62. · 2.94 Impact Factor
• Article: The mouse Pol I terminator is more efficient than the hepatitis delta virus ribozyme in generating influenza-virus-like RNAs with precise 3' ends in a plasmid-only-based virus rescue system.

  Liqiang Feng, Feng Li, Xuehua Zheng, Weiqi Pan, Kai Zhou, Yichu Liu, Hongxuan He, Ling Chen
  [show abstract] [hide abstract]
  ABSTRACT: Reverse genetics systems for generating recombinant influenza viruses are based on two different mechanisms for obtaining the 3' end of the viral RNA: one uses the self-cleaving hepatitis delta virus ribozyme (HDVR), and the other uses the murine RNA polymerase I (Pol I) terminator. In this study, we employed EGFP and Renilla luciferase reporter constructs to compare the efficiency of both methods. Our results indicate that the murine Pol I terminator was more efficient than the HDVR, which will be helpful in choosing an influenza virus rescue system, as well as in establishing other RNA virus rescue systems.
  Archives of Virology 07/2009; 154(7):1151-6. · 2.11 Impact Factor
• Article: [Rescued influenza A virus with codon deoptimized NS1 gene is attenuated both in vitro and in vivo].

  Shijia Luan, Weiqi Pan, Ting Li, Huaqiang Yang, Beiwu Zhang, Feng Li, Ling Chen
  [show abstract] [hide abstract]
  ABSTRACT: To develop novel live attenuated influenza vaccine, we explored the feasibility to attenuate influenza virus by codon deoptimization of NS1. According to the codon usage bias in influenza A virus, we designed and synthesized a condon-deoptimized NS gene by substituting codons of 110 amino acids in the NS1 gene of A/Puerto Rico/8/34(H1N1) with unpreferred synonymous codons. The influenza A virus with the codon deoptimized NS1 gene (deoNS virus) was rescued by reverse genetics. Plaque forming assay and virus growth curve showed that the growth of deoNS virus was reduced about 1000 times in MDCK cells compared to that of the wild-type virus. Intranasal inoculation with deoNS virus did not cause death or evident disease in infected BALB/c mice. Furthermore, the virus titer in the lungs of mice infected with deoNS virus was significantly lower (i.e. 100-1000 times) than that of wild-type virus. Our results indicated that influenza virus could be effectively attenuated by synonymous codon deoptimization of NS1 gene. This strategy will be useful to develop new attenuated candidates for the production of live attenuated influenza vaccines.
  Sheng wu gong cheng xue bao = Chinese journal of biotechnology 06/2009; 25(5):720-6.