Shan Lu

Publications of Shan Lu

• Cross-clade HIV-1 neutralizing antibodies induced with V3-scaffold protein immunogens following priming with gp120 DNA.

  Authors: Susan Zolla-Pazner, X-P Kong, Xunqing Jiang, Timothy Cardozo, Arthur Nádas, Sandra Cohen, Maxim Totrov, Michael S Seaman, Shixia Wang, Shan Lu

  Journal of virology. 07/2011; 85(19):9887-98.

  The V3 epitope is a known target for HIV-1 neutralizing antibodies (NAbs), and V3-scaffold fusion proteins used as boosting immunogens after gp120 DNA priming were previously shown to induce NAbs inThe V3 epitope is a known target for HIV-1 neutralizing antibodies (NAbs), and V3-scaffold fusion proteins used as boosting immunogens after gp120 DNA priming were previously shown to induce NAbs in rabbits. Here, we evaluated whether the breadth and potency of the NAb response could be improved when boosted with rationally designed V3-scaffold immunogens. Rabbits were primed with codon-optimized clade C gp120 DNA and boosted with one of five V3-cholera toxin B fusion proteins (V3-CTBs) or with double combinations of these. The inserts in these immunogens were designed to display V3 epitopes shared by the majority of global HIV-1 isolates. Double combinations of V3-CTB immunogens generally induced more broad and potent NAbs than did boosts with single V3-CTB immunogens, with the most potent and broad NAbs elicited with the V3-CTB carrying the consensus V3 of clade C (V3(C)-CTB), or with double combinations of V3-CTB immunogens that included V3(C)-CTB. Neutralization of tier 1 and 2 pseudoviruses from clades AG, B, and C and of peripheral blood mononuclear cell (PBMC)-grown primary viruses from clades A, AG, and B was achieved, demonstrating that priming with gp120 DNA followed by boosts with V3-scaffold immunogens effectively elicits cross-clade NAbs. Focusing on the V3 region is a first step in designing a vaccine targeting protective epitopes, a strategy with potential advantages over the use of Env, a molecule that evolved to protect the virus by poorly inducing NAbs and by shielding the epitopes that are most critical for infectivity.

• An E2F1-mediated DNA damage response contributes to the replication of human cytomegalovirus.

  Authors: Xiaofei E, Mary T Pickering, Michelle Debatis, Jonathan Castillo, Alexander Lagadinos, Shixia Wang, Shan Lu, Timothy F Kowalik

  PLoS pathogens. 05/2011; 7(5):e1001342.

  DNA damage resulting from intrinsic or extrinsic sources activates DNA damage responses (DDRs) centered on protein kinase signaling cascades. The usual consequences of inducing DDRs include theDNA damage resulting from intrinsic or extrinsic sources activates DNA damage responses (DDRs) centered on protein kinase signaling cascades. The usual consequences of inducing DDRs include the activation of cell cycle checkpoints together with repair of the damaged DNA or induction of apoptosis. Many DNA viruses elicit host DDRs during infection and some viruses require the DDR for efficient replication. However, the mechanism by which DDRs are activated by viral infection is poorly understood. Human cytomegalovirus (HCMV) infection induces a DDR centered on the activation of ataxia telangiectasia mutated (ATM) protein kinase. Here we show that HCMV replication is compromised in cells with inactivated or depleted ATM and that ATM is essential for the host DDR early during infection. Likewise, a downstream target of ATM phosphorylation, H2AX, also contributes to viral replication. The ATM-dependent DDR is detected as discrete, nuclear γH2AX foci early in infection and can be activated by IE proteins. By 24 hpi, γH2AX is observed primarily in HCMV DNA replication compartments. We identified a role for the E2F1 transcription factor in mediating this DDR and viral replication. E2F1, but not E2F2 or E2F3, promotes the accumulation of γH2AX during HCMV infection or IE protein expression. Moreover, E2F1 expression, but not the expression of E2F2 or E2F3, is required for efficient HCMV replication. These results reveal a novel role for E2F1 in mediating an ATM-dependent DDR that contributes to viral replication. Given that E2F activity is often deregulated by infection with DNA viruses, these observations raise the possibility that an E2F1-mediated mechanism of DDR activation may be conserved among DNA viruses.

• Two closely related Env antigens from the same patient elicited different spectra of neutralizing antibodies against heterologous HIV-1 isolates.

  Authors: Michael Vaine, Maria Duenas-Decamp, Paul Peters, Qin Liu, James Arthos, Shixia Wang, Paul Clapham, Shan Lu

  Journal of virology. 03/2011; 85(10):4927-36.

  Identification of immunogens capable of eliciting broadly neutralizing antibody (NAb) responses against HIV-1 is a major goal toward the development of an AIDS vaccine. Despite significant progressIdentification of immunogens capable of eliciting broadly neutralizing antibody (NAb) responses against HIV-1 is a major goal toward the development of an AIDS vaccine. Despite significant progress in understanding the structural features of the HIV-1 envelope glycoprotein (Env) and the discovery of multiple broadly neutralizing monoclonal antibodies with defined antigenic structures, the design of optimal Env immunogens to elicit broad NAbs remains a major challenge. As the structural determinants of Env immunogenicity remain unclear, we assessed two closely related Env antigens isolated from the same HIV-1-infected patient with different phenotypic features to identify what may result in a favorable immunogenic profile. One Env, B33, isolated from brain, was highly macrophage tropic with a high CD4 affinity, while the other, LN40, isolated from the lymph nodes, was poorly macrophage tropic with a low CD4 affinity. Using a DNA prime-protein boost approach, rabbits primed with LN40 Env antigen had a NAb response against heterologous primary isolates, while B33 Env antigens were capable of eliciting NAbs against only homologous and sensitive viral isolates. Further analysis revealed that the specificity of NAbs elicited by the LN40 antigen mapped to limited residues within or flanking the CD4 binding site. Certain key structural determinants were identified that could differentiate primary Env immunogens based on their potential to elicit broader NAbs. This progress will facilitate the rational design of effective HIV-1 vaccine formulations with optimal Env antigens.

• Dynamic changes of cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, and natural killer T (NKT) cells in patients with acute hepatitis B infection.

  Authors: Jun Li, Yaping Han, Ke Jin, Yufeng Wan, Shixia Wang, Bo Liu, Yuan Liu, Shan Lu, Zuhu Huang

  Virology journal. 01/2011; 8:199.

  The goal of this study is to observe changes in HBcAg-specific cytotoxic T lymphocytes (CTLs), natural killer (NK) and natural killer T (NKT) cells from peripheral blood and to relate such changes onThe goal of this study is to observe changes in HBcAg-specific cytotoxic T lymphocytes (CTLs), natural killer (NK) and natural killer T (NKT) cells from peripheral blood and to relate such changes on viral clearance and liver injury in patients with acute hepatitis B (AHB). Dynamic profiles on the frequency of HLA-A0201-restricted HBcAg18-27 pentamer complex (MHC-Pentamer)-specific CTLs and lymphocyte subsets in AHB patients were analyzed in addition to liver function tests, HBV serological markers, and HBV DNA levels. ELISPOT was used to detect interferon-gamma (INF-γ) secretion in specific CTLs stimulated with known T cell epitope peptides associated with HBV surface protein, polymerase, and core protein. HBV-specific CTL frequencies in AHB patients were much higher than in patients with chronic hepatitis B (CHB) (p<0.05). HBeAg and HBV DNA disappeared earlier in AHB patients with a high frequency of HBV-specific CTLs compared with those with a low frequency of HBV-specific CTLs (p=0.001 and 0.024, respectively). INF-γ spots of effector cells stimulated by Pol575-583, Env348-357, or Core18-27 epitope peptides were significantly greater in AHB patients than in CHB patients (p<0.01). CD3+CD8+ T cell numbers in AHB patients was more than observed in the healthy control group from the first to the fourth week after admission (p=0.008 and 0.01, respectively); the number of CD3+CD8+ T cells and frequency of HBcAg18-27-specific CTLs in AHB patients reached peak levels at the second week after admission. NK and NKT cell numbers were negatively correlated with the frequency of HBcAg-specific CTLs (r=-0.266, p=0.05). Patients with AHB possess a higher frequency of HBcAg-specific CTLs than CHB patients. The frequency of specific CTLs in AHB patients is correlated with HBeAg clearance indicating that HBV-specific CTLs play an important role in viral clearance and the self-limited process of the disease. Furthermore, NK and NKT cells are likely involved in the early, non-specific immune response to clear the virus.

• Influenza H5 hemagglutinin DNA primes the antibody response elicited by the live attenuated influenza A/Vietnam/1203/2004 vaccine in ferrets.

  Authors: Amorsolo L Suguitan, Xing Cheng, Weijia Wang, Shixia Wang, Hong Jin, Shan Lu

  PloS one. 01/2011; 6(7):e21942.

  Priming immunization plays a key role in protecting individuals or populations to influenza viruses that are novel to humans. To identify the most promising vaccine priming strategy, we havePriming immunization plays a key role in protecting individuals or populations to influenza viruses that are novel to humans. To identify the most promising vaccine priming strategy, we have evaluated different prime-boost regimens using inactivated, DNA and live attenuated vaccines in ferrets. Live attenuated influenza A/Vietnam/1203/2004 (H5N1) candidate vaccine (LAIV, VN04 ca) primed ferrets efficiently while inactivated H5N1 vaccine could not prime the immune response in seronegative ferrets unless an adjuvant was used. However, the H5 HA DNA vaccine alone was as successful as an adjuvanted inactivated VN04 vaccine in priming the immune response to VN04 ca virus. The serum antibody titers of ferrets primed with H5 HA DNA followed by intranasal vaccination of VN04 ca virus were comparable to that induced by two doses of VN04 ca virus. Both LAIV-LAIV and DNA-LAIV vaccine regimens could induce antibody responses that cross-neutralized antigenically distinct H5N1 virus isolates including A/HongKong/213/2003 (HK03) and prevented nasal infection of HK03 vaccine virus. Thus, H5 HA DNA vaccination may offer an alternative option for pandemic preparedness.

• Involvement of CD8+ T cell-mediated immune responses in LcrV DNA vaccine induced protection against lethal Yersinia pestis challenge.

  Authors: Shixia Wang, Jon D Goguen, Fusheng Li, Shan Lu

  Vaccine. 01/2011; 29(39):6802-9.

  Yersinia pestis (Y. pestis) is the causative pathogen of plague, a highly fatal disease for which an effective vaccine, especially against mucosal transmission, is still not available. Like manyYersinia pestis (Y. pestis) is the causative pathogen of plague, a highly fatal disease for which an effective vaccine, especially against mucosal transmission, is still not available. Like many bacterial infections, antigen-specific antibody responses have been traditionally considered critical, if not solely responsible, for vaccine-induced protection against Y. pestis. Studies in recent years have suggested the importance of T cell immune responses against Y. pestis infection but information is still limited about the details of Y. pestis antigen-specific T cell immune responses. In current report, studies are conducted to identify the presence of CD8+ T cell epitopes in LcrV protein, the leading antigen of plague vaccine development. Furthermore, depletion of CD8+ T cells in LcrV DNA vaccinated Balb/C mice led to reduced protection against lethal intranasal challenge of Y. pestis. These findings establish that an LcrV DNA vaccine is able to elicit CD8+ T cell immune responses against specific epitopes of this key plague antigen and that a CD8+ T cell immune response is involved in LcrV DNA vaccine-elicited protection. Future studies in plague vaccine development will need to examine if the presence of detectable T cell immune responses, in particular CD8+ T-cell immune responses, will enhance the protection against Y. pestis in higher animal species or humans.

• Polyvalent DNA vaccines expressing HA antigens of H5N1 influenza viruses with an optimized leader sequence elicit cross-protective antibody responses.

  Authors: Shixia Wang, Anthony Hackett, Na Jia, Chunhua Zhang, Lu Zhang, Chris Parker, An Zhou, Jun Li, Wu-Chun Cao, Zuhu Huang, Yan Li, Shan Lu

  PloS one. 01/2011; 6(12):e28757.

  Highly pathogenic avian influenza A (HPAI) H5N1 viruses are circulating among poultry populations in parts of Asia, Africa, and the Middle East, and have caused human infections with a high mortalityHighly pathogenic avian influenza A (HPAI) H5N1 viruses are circulating among poultry populations in parts of Asia, Africa, and the Middle East, and have caused human infections with a high mortality rate. H5 subtype hemagglutinin (HA) has evolved into phylogenetically distinct clades and subclades based on viruses isolated from various avian species. Since 1997, humans have been infected by HPAI H5N1 viruses from several clades. It is, therefore, important to develop strategies to produce protective antibody responses against H5N1 viruses from multiple clades or antigenic groups. In the current study, we optimized the signal peptide design of DNA vaccines expressing HA antigens from H5N1 viruses. Cross reactivity analysis using sera from immunized rabbits showed that antibody responses elicited by a polyvalent formulation, including HA antigens from different clades, was able to elicit broad protective antibody responses against multiple key representative H5N1 viruses across different clades. Data presented in this report support the development of a polyvalent DNA vaccine strategy against the threat of a potential H5N1 influenza pandemic.

• Polyvalent AIDS vaccines.

  Authors: Shan Lu, Jill M Grimes Serrano, Shixia Wang

  Current HIV research. 11/2010; 8(8):622-9.

  A major hurdle in the development of a global HIV-1 vaccine is viral diversity. For close to three decades, HIV vaccine development has focused on either the induction of T cell immune responses orA major hurdle in the development of a global HIV-1 vaccine is viral diversity. For close to three decades, HIV vaccine development has focused on either the induction of T cell immune responses or antibody responses, and only rarely on both components. After the failure of the STEP trial, the scientific community concluded that a T cell-based vaccine would likely not be protective if the T cell immune responses were elicited against only a few dominant epitopes. Similarly, for vaccines focusing on antibody responses, one of the main criticisms after VaxGen's failed Phase III trials was on the limited antigen breadth included in the two formulations used. The successes of polyvalent vaccine approaches against other antigenically variable pathogens encourage implementation of the same approach for the design of HIV-1 vaccines. A review of the existing HIV-1 vaccination approaches based on the polyvalent principle is included here to provide a historical perspective for the current effort of developing a polyvalent HIV-1 vaccine. Results summarized in this review provide a clear indication that the polyvalent approach is a viable one for the future development of an effective HIV vaccine.

• Profiles of B and T cell immune responses elicited by different forms of the hepatitis B virus surface antigen.

  Authors: Meilong Shen, Shixia Wang, Guohong Ge, Yiping Xing, Xiuwen Ma, Zuhu Huang, Shan Lu

  Vaccine. 10/2010; 28(45):7288-96.

  Gene-based hepatitis B virus (HBV) vaccines have been proposed as a novel approach to improve the immunogenicity toward non-responders and to allow for protection against potential viral escapeGene-based hepatitis B virus (HBV) vaccines have been proposed as a novel approach to improve the immunogenicity toward non-responders and to allow for protection against potential viral escape mutants. Furthermore, there is significant interest in using DNA or viral vector vaccines to serve as therapeutic agents to treat chronic HBV infections that are resistant to existing drug therapies. However, the key protective antigen of HBV, the surface protein (HBsAg), can be expressed in three different sizes due to its multiple translational initiation sites: small, middle, and large forms of HBsAg. It is not clear whether the immunogenicity of these HBsAg is same, especially their ability to elicit HBsAg-specific B cell and T cell immune responses in addition to the traditional serum HBsAg-specific antibody responses. In the current study, the immunogenicity of three forms of HBsAg DNA vaccines was analyzed individually in a mouse model. Our results indicated that different forms of the HBsAg have unique immunogenicity profiles and this information is useful for the selection of optimal gene-based HBV vaccines for further improved prophylactic and therapeutic applications.

• A versatile vector for the production of pseudotyped viruses expressing gp120 antigens from different clades of primary HIV-1 isolates.

  Authors: Zheng Wang, Mingshun Zhang, Yan Wang, Yanmei Jiao, Lu Zhang, Lin Li, Zuhu Huang, Hao Wu, Jingyun Li, Shan Lu, Shixia Wang

  Journal of virological methods. 10/2010; 171(1):183-9.

  A novel HIV-1 Env expression vector (SF162-Z) was developed by introducing two new cloning sites on the backbone of an existing vector that produces a full length Env from HIV-1 SF162 isolate. TheseA novel HIV-1 Env expression vector (SF162-Z) was developed by introducing two new cloning sites on the backbone of an existing vector that produces a full length Env from HIV-1 SF162 isolate. These sites facilitate the swapping of the gp120 portion of the SF162 Env with matching gp120 antigens from HIV-1 isolates of different genetic clades. Final production of functional pseudotyped viruses will express chimeric Env antigens, including gp41 of the parental SF162 and gp120 from other primary isolates. This system is useful for testing the neutralizing sensitivity of partial env gene products frequently identified in viral quasi species in patients infected with HIV or when only partial gp120 gene products are available.

• Profile of HIV-1 infected patients from an AIDS clinic in Beijing from 2007-2008.

  Authors: Yianmei Jiao, Tong Zhang, Shixia Wang, Qin Liu, Huifang Zhou, Shan Lu, Hao Wu

  Current HIV research. 10/2010; 8(7):515-20.

  While significant progress has been made since 2003 when a comprehensive treatment, prevention and control program was implemented to combat the HIV/AIDS epidemic in China, new challenges areWhile significant progress has been made since 2003 when a comprehensive treatment, prevention and control program was implemented to combat the HIV/AIDS epidemic in China, new challenges are emerging. There have been limited direct case reports on profiles of HIV/AIDS patients under care at unique clinical settings in China despite significant differences between clinics in this part of the world and those in Western countries. In this report, characteristics of HIV/AIDS patients managed during a 12-month period from June 2007 to May 2008 at a major medical school-affiliated AIDS clinic in the center of Beijing are described. Our data confirm an alarming trend of increased rates of sexual transmission of HIV-1 in recent years and suggest that major improvements are needed for both the type of antiviral treatments being used and post-treatment monitoring of viral load. This information will be useful for the continued progress in the clinical management of HIV/AIDS patients in China.

• Structure-guided design and immunological characterization of immunogens presenting the HIV-1 gp120 V3 loop on a CTB scaffold.

  Authors: Maxim Totrov, Xunqing Jiang, Xiang-Peng Kong, Sandra Cohen, Chavdar Krachmarov, Aidy Salomon, Constance Williams, Michael S Seaman, Ruben Abagyan, Timothy Cardozo, Miroslaw K Gorny, Shixia Wang, Shan Lu, Abraham Pinter, Susan Zolla-Pazner

  Virology. 09/2010; 405(2):513-23.

  V3 loop is a major neutralizing determinant of the HIV-1 gp120. Using 3D structures of cholera toxin B subunit (CTB), complete V3 in the gp120 context, and V3 bound to a monoclonal antibody (mAb), weV3 loop is a major neutralizing determinant of the HIV-1 gp120. Using 3D structures of cholera toxin B subunit (CTB), complete V3 in the gp120 context, and V3 bound to a monoclonal antibody (mAb), we designed two V3-scaffold immunogen constructs (V3-CTB). The full-length V3-CTB presenting the complete V3 in a structural context mimicking gp120 was recognized by the large majority of our panel of 24 mAbs. The short V3-CTB presenting a V3 fragment in the conformation observed in the complex with the 447-52D Fab, exhibited high-affinity binding to this mAb. The immunogens were evaluated in rabbits using DNA-prime/protein-boost protocol. Boosting with the full-length V3-CTB induced high anti-V3 titers in sera that potently neutralize multiple HIV virus strains. The short V3-CTB was ineffective. The results suggest that very narrow antigenic profile of an immunogen is associated with poor Ab response. An immunogen with broader antigenic activity elicits robust Ab response.

• Synergistic enhancement of immunogenicity and protection in mice against Schistosoma japonicum with codon optimization and electroporation delivery of SjTPI DNA vaccines.

  Authors: Yinchang Zhu, Fei Lu, Yang Dai, Xiaoting Wang, Jianxia Tang, Song Zhao, Chun Zhang, Hui Zhang, Shan Lu, Shixia Wang

  Vaccine. 07/2010; 28(32):5347-55.

  Schistosomiasis is an endemic, zoonotic parasitic disease caused by Schistosoma japonicum that remains a public health concern and an effective vaccine is needed. Triose-phosphate isomerase from S.Schistosomiasis is an endemic, zoonotic parasitic disease caused by Schistosoma japonicum that remains a public health concern and an effective vaccine is needed. Triose-phosphate isomerase from S. japonicum is a promising schistosome vaccine antigen shown to be immunogenic when delivered as a DNA vaccine, however, the previous S. japonicum triose-phosphate isomerase (SjTPI) DNA vaccine needs to be further optimized to achieve higher protection. In the current study, codon optimization of SjTPI DNA insert, combined with electroporation but not with the addition of a tPA leader or heat-shock protein in-frame with the SjTPI gene insert, enhanced Th1-type antibody and cytokine production and most significantly, achieved great than 50% reduction of infection against challenge with S. japonicum cercariae, a major milestone in S. japonicum vaccine development. Our results suggest that the combination of a codon optimized vaccine design and an efficient vaccine delivery system can greatly improve the potential of a SjTPI DNA vaccine as a viable schistosome vaccine candidate.

• EV71: an emerging infectious disease vaccine target in the Far East?

  Authors: Juan Xu, Yuan Qian, Shixia Wang, Jill M Grimes Serrano, Wei Li, Zuhu Huang, Shan Lu

  Vaccine. 03/2010; 28(20):3516-21.

  Hand, foot, and mouth disease (HFMD) is a common viral illness in infants and children caused by viruses that belong to the enterovirus genus of the picornavirus family. Although most HFMD do notHand, foot, and mouth disease (HFMD) is a common viral illness in infants and children caused by viruses that belong to the enterovirus genus of the picornavirus family. Although most HFMD do not result in serious complications, outbreaks of HFMD caused by enterovirus 71 (EV71) can present with a high rate of neurological complications, including meningoencephalitis, pulmonary complications, and possibly death. HFMD caused by EV71 has become a major emerging infectious disease in Asia and the highly pathogenic potential of EV71 clearly requires the attention of world medical community. Although vaccine development for EV71 is active and ongoing in Asian countries, a greater joint effort is needed for vaccine researchers and developers in both developed and developing countries to produce a safe and effective EV71 vaccine.

• Increased immunogenicity of HIV-1 p24 and gp120 following immunization with gp120/p24 fusion protein vaccine expressing alpha-gal epitopes.

  Authors: Ussama M Abdel-Motal, Shixia Wang, Amany Awad, Shan Lu, Kim Wigglesworth, Uri Galili

  Vaccine. 02/2010; 28(7):1758-65.

  Developing an effective HIV-1 vaccine will require strategies to enhance antigen presentation to the immune system. In a previous study we demonstrated a marked increase in immunogenicity of theDeveloping an effective HIV-1 vaccine will require strategies to enhance antigen presentation to the immune system. In a previous study we demonstrated a marked increase in immunogenicity of the highly glycosylated HIV-1 gp120 protein following enzymatic addition of alpha-gal epitopes to the carbohydrate chains. In the present study we determined whether gp120(alphagal) can also serve as an effective platform for targeting other HIV-1 proteins to APC and thus increase immunogenicity of both proteins. For this purpose we produced a recombinant fusion protein between gp120 and the HIV-1 matrix p24 protein (gp120/p24). Multiple alpha-gal epitopes were synthesized enzymatically on the gp120 portion of the fusion protein to generate a gp120(alphagal)/p24 vaccine. Immune responses to gp120(alphagal)/p24 compared to gp120/p24 vaccine lacking alpha-gal epitopes were evaluated in alpha1,3galactosyltransferase knockout (KO) mice. These mice lack alpha-gal epitopes and, therefore, are capable of producing the anti-Gal antibody. T cell responses to p24, as assessed by ELISPOT and by CD8+ T cells intracellular staining assays for IFNgamma, was on average 12- and 10-fold higher, respectively, in gp120(alphagal)/p24 immunized mice than in mice immunized with gp120/p24. In addition, cellular and humoral immune responses against gp120 were higher by 10-30-fold in mice immunized with gp120(alphagal)/p24 than in gp120/p24 immunized mice. Our data suggest that the alpha-gal epitopes on the gp120 portion of the fusion protein can significantly augment the immunogenicity of gp120, as well as that of the fused viral protein which lacks alpha-gal epitopes. This strategy of anti-Gal mediated targeting to APC may be used for production of effective HIV-1 vaccines comprised of various viral proteins fused to gp120.

• Antibody responses elicited through homologous or heterologous prime-boost DNA and protein vaccinations differ in functional activity and avidity.

  Authors: Michael Vaine, Shixia Wang, Anthony Hackett, James Arthos, Shan Lu

  Vaccine. 02/2010; 28(17):2999-3007.

  Using a gp120 envelope glycoprotein from the JR-FL strain of human immunodeficiency virus-1 (HIV-1) as a model antigen, the goal of the current study was to evaluate the level and quality of antibodyUsing a gp120 envelope glycoprotein from the JR-FL strain of human immunodeficiency virus-1 (HIV-1) as a model antigen, the goal of the current study was to evaluate the level and quality of antibody responses elicited by different prime-boost vaccination regimens (protein only, DNA only, DNA plus protein) in rabbits. Our data demonstrated that incorporating DNA immunization as a prime in a heterologous prime-boost regimen was able to elicit a more diverse and conformational epitope profile, higher antibody avidity, and improved neutralizing activity than immunization with only protein. Additionally, this improved neutralizing activity was observed in spite of similar antibody specificities and avidities seen when only DNA vaccination was used, providing additional evidence that the use of a combination immunization regimen increases the protective antibody response. Insights gained from the current study confirmed that the heterologous DNA prime-protein boost approach is effective in eliciting not only high level but also improved quality of antigen-specific antibody responses, and thus may offer a new technology platform to develop better and safer subunit vaccines.

• Antigen engineering can play a critical role in the protective immunity elicited by Yersinia pestis DNA vaccines.

  Authors: Shixia Wang, Innocent Mboudjeka, Jon D Goguen, Shan Lu

  Vaccine. 02/2010; 28(8):2011-9.

  The use of a DNA immunization approach to deliver protective antigens against Yersinia pestis (Y. pestis) has been successful in previously reported studies. In the current study, the gene designsThe use of a DNA immunization approach to deliver protective antigens against Yersinia pestis (Y. pestis) has been successful in previously reported studies. In the current study, the gene designs for V and F1, two well-studied virulent factors serving as main targets for vaccine development, were altered to explore additional options in hopes of improving the protective immunity of DNA vaccines expressing these two antigens. Compared to the wild type V gene DNA vaccines, the use of codon optimized V gene sequences was effective in improving the antigen expression, titers of anti-V antibody responses, and survival against a mucosal lethal challenge. For the F1 DNA vaccine, removal of the N-terminal hydrophobic region was able to improve protective immunity. However, adding a mammalian signal peptide sequence to F1 actually led to reduced protection despite it inducing slightly higher anti-F1 antibody responses. The F1 gene can be fused with a gene coding for YscF, a newly confirmed partial protective antigen for Y. pestis, to produce DNA vaccines that express fused F1 and YscF antigens. One design, in particular, that had YscF fused to the downstream sequence of F1, produced better protection than separate F1 or YscF DNA vaccines, suggesting a potential synergistic effect between these two antigens. Findings from the above studies indicated that there are multiple approaches to optimize the protective immunity for plague DNA vaccines. Most importantly, proper antigen engineering to produce optimal antigen gene inserts in DNA vaccines can clearly play a major role in the future designs of a wide range of DNA vaccines.

• Profiles of human serum antibody responses elicited by three leading HIV vaccines focusing on the induction of Env-specific antibodies.

  Authors: Michael Vaine, Shixia Wang, Qin Liu, James Arthos, David Montefiori, Paul Goepfert, M Juliana McElrath, Shan Lu

  PloS one. 01/2010; 5(11):e13916.

  In the current report, we compared the specificities of antibody responses in sera from volunteers enrolled in three US NIH-supported HIV vaccine trials using different immunization regimens. HIV-1In the current report, we compared the specificities of antibody responses in sera from volunteers enrolled in three US NIH-supported HIV vaccine trials using different immunization regimens. HIV-1 Env-specific binding antibody, neutralizing antibody, antibody-dependent cell-mediated cytotoxicity (ADCC), and profiles of antibody specificity were analyzed for human immune sera collected from vaccinees enrolled in the NIH HIV Vaccine Trial Network (HVTN) Study #041 (recombinant protein alone), HVTN Study #203 (poxviral vector prime-protein boost), and the DP6-001 study (DNA prime-protein boost). Vaccinees from HVTN Study #041 had the highest neutralizing antibody activities against the sensitive virus along with the highest binding antibody responses, particularly those directed toward the V3 loop. DP6-001 sera showed a higher frequency of positive neutralizing antibody activities against more resistant viral isolate with a significantly higher CD4 binding site (CD4bs) antibody response compared to both HVTN studies #041 and #203. No differences were found in CD4-induced (CD4i) antibody responses, ADCC activity, or complement activation by Env-specific antibody among these sera. Given recent renewed interest in realizing the importance of antibody responses for next generation HIV vaccine development, different antibody profiles shown in the current report, based on the analysis of a wide range of antibody parameters, provide critical biomarker information for the selection of HIV vaccines for more advanced human studies and, in particular, those that can elicit antibodies targeting conformational-sensitive and functionally conserved epitopes.

• Technical transformation of biodefense vaccines.

  Authors: Shan Lu, Shixia Wang

  Vaccine. 11/2009; 27 Suppl 4:D8-D15.

  Biodefense vaccines are developed against a diverse group of pathogens. Vaccines were developed for some of these pathogens a long time ago but they are facing new challenges to move beyond the oldBiodefense vaccines are developed against a diverse group of pathogens. Vaccines were developed for some of these pathogens a long time ago but they are facing new challenges to move beyond the old manufacturing technologies. New vaccines to be developed against other pathogens have to determine whether to follow traditional vaccination strategies or to seek new approaches. Advances in basic immunology and recombinant DNA technology have fundamentally transformed the process of formulating a vaccine concept, optimizing protective antigens, and selecting the most effective vaccine delivery approach for candidate biodefense vaccines.

• Immunogenicities of Env glycoproteins from circulating HIV-1 isolates in China focusing on the strategy of "DNA prime plus protein boost".

  Authors: Zheng Wang, Shi-xia Wang, Si-yang Liu, Zuo-yi Bao, Dao-min Zhuang, Lin Li, Chun-hua Zhang, Lu Zhang, Jing-yun Li, Shan Lu

  Chinese medical journal. 10/2009; 122(19):2339-45.

  The adenovirus-based HIV-1 vaccine developed by Merck Company suffered from an unexpected failure in September 2007. This generated a big shift in the strategy of HIV vaccine development with renewedThe adenovirus-based HIV-1 vaccine developed by Merck Company suffered from an unexpected failure in September 2007. This generated a big shift in the strategy of HIV vaccine development with renewed focus on the induction of neutralizing antibodies. A major challenge in developing an HIV-1 vaccine is to identify immunogens and adopt delivery methods that can elicit broadly neutralizing antibodies against primary isolates of different genetic subtypes. Most circulating HIV-1 isolates in China are composed of clades Thai-B, CRF_BC and CRF01_AE. In order to construct DNA vaccines against these 3 HIV-1 subtypes, DNA vaccines carrying the gp120 regions from HIV-1 isolates of GX48(AE), GX79(AE), NX22(BC), GS22(BC), HN24(Thai-B) were constructed. Expression of gp120 from these DNA vaccines was detected by Western blotting in transiently transfected 293T cells. Pilot immunizations of New Zealand white rabbits were performed using the strategy of "DNA prime plus protein boost" and the neutralizing antibody response was detected in a Tzm-bl cell based assay against different HIV-1 strains. Response of gp120-specific antibody was relatively low after DNA primes (mean titer = 10(4.72)); however, the titer of gp120-specific antibody went up with 2 protein boosts (mean titer = 10(6.81)). Above all, neutralizing antibody (Nab) titers induced by this combined approach were much better than those elicited by DNA or protein used alone (P < 0.01). Neutralizing activities of immunized rabbit sera against several pseudoviruses and laboratorial strains were evaluated, most rabbit sera primed with monovalent vaccine were capable of neutralizing only 1 of 5 viruses, however, sera primed with the polyvalent DNA vaccines were able to neutralize at least 2 of 5 viruses. Polyvalent DNA prime plus protein boost is an effective immunization strategy to broaden the neutralization breadth and further research should be performed on the basis of this pilot study.