Abstract
In 1796, Edward Jenner introduced the concept of vaccination with cowpox virus, an Orthopoxvirus within the family Poxviridae that elicits cross protective immunity against related orthopoxviruses, including smallpox virus (variola virus). Over time, vaccinia virus (VACV) replaced cowpox virus as the smallpox vaccine, and vaccination efforts eventually led to the successful global eradication of smallpox in 1979. VACV has many characteristics that make it an excellent vaccine and that were crucial for the successful eradication of smallpox, including (1) its exceptional thermal stability (a very important but uncommon characteristic in live vaccines), (2) its ability to elicit strong humoral and cell-mediated immune responses, (3) the fact that it is easy to propagate, and (4) that it is not oncogenic, given that VACV replication occurs exclusively within the host cell cytoplasm and there is no evidence that the viral genome integrates into the host genome. Since the eradication of smallpox, VACV has experienced a renaissance of interest as a viral vector for the development of recombinant vaccines, immunotherapies, and oncolytic therapies, as well as the development of next-generation smallpox vaccines. This revival is mainly due to the successful use and extensive characterization of VACV as a vaccine during the smallpox eradication campaign, along with the ability to genetically manipulate its large dsDNA genome while retaining infectivity and immunogenicity, its wide mammalian host range, and its natural tropism for tumor cells that allows its use as an oncolytic vector. This review provides an overview of new uses of VACV that are currently being explored for the development of vaccines, immunotherapeutics, and oncolytic virotherapies.
Next-Generation Smallpox Vaccines
Smallpox was successfully eradicated through the efforts of the World Health Organization (WHO) in 1979.Citation1,Citation2 However, in the last decade there has been a renewed interest in the development of next-generation smallpox vaccines due to the threat of bioterrorism and the possible emergence of other orthopoxviruses (such as monkeypox virus) as significant human pathogens. Although the smallpox vaccines used during the smallpox eradication campaign (now called first-generation vaccines) were very efficacious, they were typically propagated in the skin of calvesCitation2 under conditions that did not adhere to good manufacturing practices (GMP). VACV strains widely used during the smallpox eradication campaign included the New York City Board of Health (NYCBH), Lister, and EM-63 (). These live vaccines were commonly administered by scarification with a bifurcated needle, leading to a cutaneous reaction due to local virus replication. The resulting scar at the site of inoculation, known as the “take,” has been historically accepted as the correlate of protection for smallpox.Citation1-Citation3 However, these first-generation smallpox vaccines were associated with a number of adverse reactions ranging from mild (e.g., malaise, mild rash, and fever) to severe (e.g., eczema vaccinatum, progressive vaccinia, and post-vaccinial encephalitis).Citation2,Citation4 Over the years, susceptibility to more severe complications was correlated with pre-existing conditions such as atopic dermatitis, immunosupression (e.g., due to HIV/AIDS and immunosuppressive therapy), and cardiac disease. Individuals with such conditions, or with contacts that have such conditions, are currently contraindicated for smallpox vaccination.Citation5,Citation6
Table 1. Some first and next-generation smallpox vaccines
A number of second-generation vaccines have been developed focusing on sterile cell culture techniques for vaccine propagation (). For example, the Elstree-BN vaccine developed by Bavarian Nordic was grown in chick embryo fibroblasts,Citation7 and the cell-cultured smallpox vaccine (CCSV) developed by DynPort Vaccine Company was derived from the NYCBH strain grown on normal diploid MRC-5 human lung cell cultures.Citation8 Similarly, Acambis (now part of Sanofi Pasteur) isolated a single clone derived from the Dryvax vaccine that was grown in Vero cells and named ACAM2000.Citation9 ACAM2000 was less neurovirulent than Dryvax in mice and nonhuman primates,Citation10 provided equivalent immunogenicity in clinical trials,Citation11 and was licensed in 2007 in the US.Citation12 However, the overall safety profile of ACAM2000 and other second-generation smallpox vaccines is still comparable to the first-generation vaccines such as Dryvax, with similar rates of complications.Citation11
A number of highly attenuated strains of VACV have been developed and are now being considered as safer smallpox vaccine alternatives, called third-generation smallpox vaccines (). One example is modified vaccinia Ankara (MVA), that was developed by passage of VACV strain Ankara over 570 times in chick embryo fibroblasts.Citation13 Inoculation with MVA leads to abortive infections in mammals and most mammalian cells, but expression of viral genes still occurs.Citation14 This highly attenuated VACV strain has been extensively tested in humans and has sparked considerable interest because it has been demonstrated to be extremely safe.Citation15 However, MVA propagation is limited to chick embryo fibroblasts and a few other mammalian cell lines where yield is low,Citation14 and the immunogenicity is not as robust compared with previous smallpox vaccine generations. For example, immune responses in phase I and II clinical trials to an MVA-based vaccine developed by Bavarian Nordic (Imvamune®) are dose-dependent and can require two immunizations to achieve immune responses similar to first-generation vaccines.Citation16,Citation17
Genetic manipulation of the VACV genome has also played a role in the development of highly attenuated VACV strains. The Copenhagen strain of VACV was considered to have higher pathogenicity,Citation2 but the deletion of 18 non-essential genes led to the highly attenuated NYVAC strain that is still immunogenic.Citation18,Citation19 However, NYVAC induces lower antibody responses in humans when compared with Dryvax or Lister first-generation vaccine strains, and it does not induce anti-A27 antibodies that are seen in the immune response to first-generation vaccines and can neutralize intracellular mature virus (IMV).Citation20 Two major disadvantages of highly attenuated VACV strains such as MVA and NYVAC is that they do not produce a “take” in vaccinees and their efficacy against smallpox was never determined.
An additional third-generation vaccine is LC16m8, an attenuated VACV derived from the Lister strain that has an excellent safety profile.Citation21-Citation23 LC16m8 contains a mutation in the B5R gene, which causes the virus to produce smaller plaques and replicate less efficiently in Vero cells,Citation24,Citation25 but unlike MVA, LC16m8 produces a “take” in vaccinees.Citation22,Citation23 This vaccine was licensed in Japan and used in the 1970s eradication campaign, but since smallpox was no longer endemic at that time, its efficacy against smallpox is currently unknown. A disadvantage that must be considered is that LC16m8 does not induce neutralizing antibodies against the B5 protein, the main target for extracellular enveloped virus (EEV) neutralizing antibodies.Citation26
A number of different approaches are being used for the development of the so-called fourth-generation smallpox vaccines that eliminate the possibility of the VACV vector to cause adverse events or revert to a more pathogenic phenotype (). These include the development of subunit and DNA vaccines typically composed of VACV (or variola virus counterpart) membrane proteins that elicit neutralizing antibodies against the IMV and EEV forms of the virus.Citation27-Citation33 A particularly new approach is the use of conserved and immunogenic multi-T-cell epitopes that are used in a DNA-prime, peptide boost vaccine regimen.Citation34 These fourth-generation vaccines have shown to be protective using animal models, but none are currently being tested in clinical trials, and to be efficacious against smallpox they will likely require booster immunizations.
Vaccinia Viruses as Animal Vaccine Vectors
The successful use and extensive characterization of VACV during the smallpox eradication campaign, along with the ability to genetically manipulate its large dsDNA genome while retaining infectivity, its heat stability and low cost of production, makes VACV particularly attractive for the development of animal vaccines.Citation35,Citation36 A large number of antigens from animal pathogens have been expressed in VACV, and the majority elicit protective immune responses (examples shown in ). The most successful recombinant VACV vaccine has been the oral vaccine for sylvatic rabies (Raboral V-RG®) that expresses the rabies glycoprotein (G).Citation37,Citation38 This recombinant virus is packaged into vaccine baits that are distributed in areas affected by rabies. The heat stability of the V-RG vaccine proved to be extremely helpful in sylvatic rabies vaccination programs, which have led to better control of rabies in Europe and North America.Citation39 Several recombinant VACV vaccines engineered to express the fusion and hemagglutinin glycoproteins of rinderpest virus have also been developed,Citation40,Citation41 providing sterilizing immunity to cattle challenged with virulent rinderpest virus over one year after vaccination.Citation41 Recombinant VACVs expressing heterologous viral antigens have also been protective against peste-des-petits-ruminants virus, vesicular stomatitis virus, Newcastle disease virus, canine distemper virus, and Rift Valley fever virus in a variety of animal species (reviewed in ).
Table 2. Some vaccinia virus-vectored animal vaccines
Vaccinia Viruses as Human Vaccine Vectors
The use of VACV as a vector for human vaccines against infections agents has also been extensively investigated (), with most of the effort focused on the development of vaccines against HIV. Initially, replication-competent VACVs were typically employed, but more recent efforts center on the use of replication-defective poxviruses due to safety concerns. In addition, replication-defective poxvirus vectors, including MVA, NYVAC, and avipoxviruses (such as canarypox virus and fowlpox virus), offer the advantage of allowing multiple booster immunizations even in subjects with pre-existing immunity.Citation42 The only Phase III trial to show any evidence of protection against HIV has been the RV144 trial in Thailand.Citation43 The RV144 vaccine regimen consisted of four priming injections of a recombinant canarypox expressing HIV-1 Gag, protease, and Env, followed by two booster immunizations with a recombinant Env subunit vaccine. The trial involved 16,402 subjects and the estimated vaccine efficacy (prevention of HIV-1 infection) was 31.2%.Citation43 The results from the RV144 Thai trial, albeit modest, reinvigorated the HIV vaccine community and their interest in poxvirus-vectored HIV vaccines. A number of Phase I and II HIV clinical trials, usually in the form of a DNA prime and recombinant MVA or NYVAC boost, have shown that these vaccine regimens are safe, immunogenic, and have the potential to improve the efficacy obtained with the RV144 Thai trial ().
Table 3. Some vaccinia virus-vectored human vaccines
Recombinant MVA has also been extensively used alone or in prime-boost strategies in vaccine clinical trials for other viral diseases such as influenza and hepatitis B, as well as bacterial and parasitic diseases such as tuberculosis and malaria (). Three malaria Phase I trials with recombinant chimpanzee adenovirus (ChAd63) and MVA expressing different Plasmodium falciparum antigens have shown that this prime-boost strategy is safe and immunogenic.Citation44-Citation46 Likewise, Phase I trials with an MVA vector expressing the Mycobacterium tuberculosis 85A antigen, aimed to serve as a booster immunization after bacille Calmette-Guerin (BCG) vaccination, showed that the vaccine can induce potent Th1 responses.Citation47 Lastly, a number of other constructs are being developed and investigated in pre-clinical trials, including vaccines against hepatitis C virus,Citation48 respiratory syncytial virus,Citation49 anthrax (with the advantage of being a dual vaccine against anthrax and smallpox),Citation50 and Nipah virus.Citation51
Vaccinia Viruses as Immunotherapeutic Cancer Vectors
The ability of VACV to induce potent immune responses to tumor-associated antigens (TAAs) expressed in its genome has been employed for the development of immunotherapies for cancer (). One example is PROSTVAC® (Bavarian Nordic), a therapeutic cancer vaccine for prostate cancer that consists of a replication-competent VACV prime followed by multiple replication-defective avian poxvirus (fowlpox) boosts.Citation52,Citation53 Both poxviruses express a modified prostate-specific antigen (PSA), along with three T-cell costimulatory molecules termed TRICOM (B7.1, ICAM-1, and LFA-3). The immune response to the altered PSA (with a single amino acid change in an HLA-A2 epitope) is aimed to target cancerous prostate cells, while the costimulatory molecules increase the immunogenicity of the constructs. This treatment has been studied in Phase II clinical trials in patients with metastatic castration-resistant prostate cancer, where treatment was well tolerated, death rate was reduced by 44%, and the median overall survival was 8.5 mo longer than in patients receiving control vectors.Citation52,Citation53 This increase in overall survival was noticeably superior to that afforded by the currently approved treatment (docetaxel, 2–3 mo increase in overall survival), and Phase III clinical trials are ongoing.Citation52,Citation54 Bavarian Nordic is also performing clinical trials with an MVA vector (MVA-BN® PRO) expressing two prostate TAAs, PSA along with prostatic acid phosphatase (PAP),Citation54,Citation55 and with MVA-BN® HER2, an MVA vector expressing the TAA human epidermal growth factor receptor 2 (HER2) to treat breast cancer.Citation54,Citation56
Table 4. Some vaccinia virus vectors used for cancer immunotherapy
TroVax® (Oxford BioMedica) is an MVA vector that expresses the human oncofetal antigen 5T4, a placental glycoprotein overexpressed in a number of different cancers ().Citation57 When administered alone or in conjuction with other treatments (e.g., chemotherapy and cytokines), Trovax® mounted high anti-5T4 immune responses that were associated with increased overall survival.Citation54,Citation57-Citation61 Poxvirus vectors expressing another TAA, the cancer-testis NY-ESO-1 antigen, were tested in Phase II clinical trials in a VACV prime followed by fowlpox boost regimen with melanoma and ovarian cancer patients that were at risk for recurrence or progression after completion of their primary therapy.Citation54,Citation62 The trials provided evidence for an extended overall survival and progression-free survival in patients that developed detectable anti-NY-ESO-1 immune responses.Citation62
TG4010 (Transgene SA) is an MVA vector that expresses mucin-1 (MUC-1), a TAA expressed by glandular epithelia and by some cancers, as well as the immostimulatory cytokine IL-2 ().Citation63 Results from a Phase IIb study with non-small-cell lung cancer patients in combination with chemotherapy suggests that TG4010 has beneficial effects and additional trials are ongoing.Citation54,Citation64 Finally, CV-301 (Bavarian Nordic), formerly known as PANVAC, is an MVA vector that in addition to MUC-1, also expresses carcinoembryonic antigen (CEA) and the TRICOM set of T-cell costimulatory molecules, having a potential effect on multiple cancers.Citation65 A recent pilot study in patients with metastatic breast and ovarian cancer suggests that CV-301 may be beneficial to patients and a Phase II study is underway.Citation54,Citation65
Vaccinia Viruses as Oncolytic Cancer Therapy Vectors
Oncolytic viruses are promising new therapies for the clinical treatment of cancers. As a replication-competent virus, VACV displays a natural tumor tropism and kills cancer cells through apoptosis and other mechanisms.Citation66 Moreover, recombinant VACVs in which the vaccinia growth factor (VGF) and thymidine kinase (TK) genes have been deleted acquire enhanced tumor selectivity (tropism), likely because cancer cells overexpress epidermal growth factor receptor (EGFR) and have high metabolic rates that make TK expression by VACV dispensable.Citation67,Citation68 Systemic administration of these oncolytic VACV vectors (e.g., intravenously) targets both tumors and metastases, and current clinical trials show that VACV vectors can be an effective oncolytic cancer therapy (). In addition, recombinant VACVs expressing host immunomodulating genes such as human GM-CSF and other cytokines, anti-angiogenic agents, and extracellular matrix genes also show enhanced tumor selectivity and oncolytic effects.Citation66 For example, JX-594 (Jennerex Biotherapeutics) is a TK negative VACV expressing GM-CSF. In patients with hepatocellular carcinoma, treatment with JX-594 resulted in antitumor and antivascular activities,Citation69 and in clinical trials patients with metastatic liver cancer and metastatic melanoma tolerated treatment and anti-tumor effects were observed.Citation70,Citation71 Another example is vvDD-CDSR (Jennerex Biotherapeutics), a TK and VGF negative vector engineered to express a reporting gene (somatostatin receptor) for molecular in vivo imaging after systemic delivery, as well as the prodrug-activating enzyme cytosine deaminase for therapy with 5-fluorocytosine.Citation72,Citation73 These modifications allow vvDD-CDSR to be highly tumor selective and oncolytic. Finally, GL-ONC1 (Genelux), also known as GLV-1h68, is a light-emitting oncolytic VACV expressing a luciferase-green fluorescent protein (GFP) fusion gene and containing deletions in the F14.5L, TK, and A56R genes.Citation74 In pre-clinical trials it showed tumor-specific replication and solid tumor size reduction.Citation74-Citation76 In addition, VACVs with tumor selectivity and light-emitting or imaging features (such as expression of somatostatin receptor and 111In-pentreteodide treatment) can be innovative and helpful tools to non-invasively detect and locate primary and metastatic tumors, as well as to track the therapeutic vector during treatment.Citation72,Citation77
Table 5. Some vaccinia virus vectors used for oncolytic cancer therapy
Future Perspectives
Since the eradication of smallpox more than 30 y ago, VACV has experienced a renaissance of interest as a viral vector for the development of recombinant vaccines, immunotherapies, and oncolytic therapies, as well as the development of next-generation smallpox vaccines. This renewed interest in both replication-competent and replication-defective VACVs has driven a number of vaccine and therapeutic candidates to clinical trials. Replication-competent VACVs are used for oncolytic therapy, and as live vaccines they elicit superior immune responses, but safety is a concern due to potential adverse events. Conversely, replication-defective VACVs are not as immunogenic as their replication-competent counterparts, but are extremely safe and offer the capacity to be administered multiple times with minimal interference from pre-existing immunity. A number of approaches have been used to enhance the safety of replication-competent VACV vectors while maintaining their immunogenicity, such as the deletion of viral genes and expression of cytokines. A new approach under development to generate next-generation smallpox vaccines that are efficacious and safer is the addition of safety mechanisms to second-generation VACV vectors that should allow the conditional replication of the virus and the production of the “take,” the correlate of protection against smallpox (Hagen, Titong, and Verardi, unpublished data). With these built-in safety systems, VACV replication can be controlled so that adverse events in vaccinees and contacts can be treated with antibiotics. These new technologies can also be applied for the development of VACV vectors for human vaccines and therapies with enhanced safety features.
A range of potential new uses is under development in areas such as tumor imaging and enhanced oncolytic and tumor selectivity. The fact that VACV has the capacity to hold at least 25 kb of heterologous DNA while retaining infectivity also enables the development of multi-pathogen, multi-epitope polyvalent vaccines. Hence, it seems inevitable that this “old” vaccine will lead to “new” uses in the near and distant future.
| Abbreviations: | ||
| VACV | = | vaccinia virus |
| MVA | = | modified vaccinia Ankara |
| IMV | = | intracellular mature virus |
| EEV | = | extracellular enveloped virus |
| TAA | = | tumor-associated antigen |
| TK | = | thymidine kinase |
| FDA | = | Food and Drug Administration |
Acknowledgments
The authors would like to thank Caitlin O’Connell for critical review of the manuscript. Work in our laboratory is currently supported by the US Department of Agriculture (USDA), the University of Connecticut Research Foundation (UCRF), and the University of Connecticut Office of Undergraduate Research (OUR).
Related Research Data
References
- Wehrle PF. A reality in our time--certification of the global eradication of smallpox. J Infect Dis 1980; 142:636 - 8; http://dx.doi.org/10.1093/infdis/142.4.636; PMID: 7003037
- Fenner F, Henderson DA, Arita I, Jeek Z, Ladnyi ID. Smallpox and its eradication. Geneva, Switzerland: World Health Organization, 1988.
- Moss B. Poxviridae: the viruses and their replication. In: Knipe DM, Howley PM, eds. Fields' virology. Philadelphia: Lippincott Williams & Wilkins, 2007:2906-45.
- Lane JM, Ruben FL, Neff JM, Millar JD. Complications of smallpox vaccination, 1968: results of ten statewide surveys. J Infect Dis 1970; 122:303 - 9; http://dx.doi.org/10.1093/infdis/122.4.303; PMID: 4396189
- Lane JM, Goldstein J. Evaluation of 21st-century risks of smallpox vaccination and policy options. Ann Intern Med 2003; 138:488 - 93; PMID: 12639083
- Kemper AR, Davis MM, Freed GL. Expected adverse events in a mass smallpox vaccination campaign. Eff Clin Pract 2002; 5:84 - 90; PMID: 11990216
- Stittelaar KJ, van Amerongen G, Kondova I, Kuiken T, van Lavieren RF, Pistoor FH, et al. Modified vaccinia virus Ankara protects macaques against respiratory challenge with monkeypox virus. J Virol 2005; 79:7845 - 51; http://dx.doi.org/10.1128/JVI.79.12.7845-7851.2005; PMID: 15919938
- Greenberg RN, Kennedy JS, Clanton DJ, Plummer EA, Hague L, Cruz J, et al. Safety and immunogenicity of new cell-cultured smallpox vaccine compared with calf-lymph derived vaccine: a blind, single-centre, randomised controlled trial. Lancet 2005; 365:398 - 409; PMID: 15680454
- Weltzin R, Liu J, Pugachev KV, Myers GA, Coughlin B, Blum PS, et al. Clonal vaccinia virus grown in cell culture as a new smallpox vaccine. Nat Med 2003; 9:1125 - 30; http://dx.doi.org/10.1038/nm916; PMID: 12925845
- Monath TP, Caldwell JR, Mundt W, Fusco J, Johnson CS, Buller M, et al. ACAM2000 clonal Vero cell culture vaccinia virus (New York City Board of Health strain)--a second-generation smallpox vaccine for biological defense. Int J Infect Dis 2004; 8:Suppl 2 S31 - 44; PMID: 15491873
- Frey SE, Newman FK, Kennedy JS, Ennis F, Abate G, Hoft DF, et al. Comparison of the safety and immunogenicity of ACAM1000, ACAM2000 and Dryvax in healthy vaccinia-naive adults. Vaccine 2009; 27:1637 - 44; http://dx.doi.org/10.1016/j.vaccine.2008.11.079; PMID: 19071184
- Greenberg RN, Kennedy JS. ACAM2000: a newly licensed cell culture-based live vaccinia smallpox vaccine. Expert Opin Investig Drugs 2008; 17:555 - 64; http://dx.doi.org/10.1517/13543784.17.4.555; PMID: 18363519
- Mayr A, Stickl H, Müller HK, Danner K, Singer H. [The smallpox vaccination strain MVA: marker, genetic structure, experience gained with the parenteral vaccination and behavior in organisms with a debilitated defence mechanism (author’s transl)]. Zentralbl Bakteriol B 1978; 167:375 - 90; PMID: 219640
- Drexler I, Heller K, Wahren B, Erfle V, Sutter G. Highly attenuated modified vaccinia virus Ankara replicates in baby hamster kidney cells, a potential host for virus propagation, but not in various human transformed and primary cells. J Gen Virol 1998; 79:347 - 52; PMID: 9472619
- Hochstein-Mintzel V, Hänichen T, Huber HC, Stickl H. [An attenuated strain of vaccinia virus (MVA). Successful intramuscular immunization against vaccinia and variola (author’s transl)]. Zentralbl Bakteriol Orig A 1975; 230:283 - 97; PMID: 1146441
- Vollmar J, Arndtz N, Eckl KM, Thomsen T, Petzold B, Mateo L, et al. Safety and immunogenicity of IMVAMUNE, a promising candidate as a third generation smallpox vaccine. Vaccine 2006; 24:2065 - 70; http://dx.doi.org/10.1016/j.vaccine.2005.11.022; PMID: 16337719
- von Krempelhuber A, Vollmar J, Pokorny R, Rapp P, Wulff N, Petzold B, et al. A randomized, double-blind, dose-finding Phase II study to evaluate immunogenicity and safety of the third generation smallpox vaccine candidate IMVAMUNE. Vaccine 2010; 28:1209 - 16; http://dx.doi.org/10.1016/j.vaccine.2009.11.030; PMID: 19944151
- Tartaglia J, Perkus ME, Taylor J, Norton EK, Audonnet JC, Cox WI, et al. NYVAC: a highly attenuated strain of vaccinia virus. Virology 1992; 188:217 - 32; http://dx.doi.org/10.1016/0042-6822(92)90752-B; PMID: 1566575
- Paoletti E, Tartaglia J, Taylor J. Safe and effective poxvirus vectors--NYVAC and ALVAC. Dev Biol Stand 1994; 82:65 - 9; PMID: 7958484
- Midgley CM, Putz MM, Weber JN, Smith GL. Vaccinia virus strain NYVAC induces substantially lower and qualitatively different human antibody responses compared with strains Lister and Dryvax. J Gen Virol 2008; 89:2992 - 7; http://dx.doi.org/10.1099/vir.0.2008/004440-0; PMID: 19008384
- Hashizume S, Yoshizawa H, Morita M, Suzuki K. Properties of attenuated mutant of vaccinia virus, LC16M8, derived from Lister strain. In: Quinnan GV, ed. Vaccinia viruses as vectors for vaccine antigens Proceedings of the Workshop on Vaccinia Viruses as Vectors for Vaccine Antigens. New York, N.Y.: Elsevier, 1985:87-99.
- Saito T, Fujii T, Kanatani Y, Saijo M, Morikawa S, Yokote H, et al. Clinical and immunological response to attenuated tissue-cultured smallpox vaccine LC16m8. JAMA 2009; 301:1025 - 33; http://dx.doi.org/10.1001/jama.2009.289; PMID: 19278946
- Kennedy JS, Gurwith M, Dekker CL, Frey SE, Edwards KM, Kenner J, et al. Safety and immunogenicity of LC16m8, an attenuated smallpox vaccine in vaccinia-naive adults. J Infect Dis 2011; 204:1395 - 402; http://dx.doi.org/10.1093/infdis/jir527; PMID: 21921208
- Takahashi-Nishimaki F, Funahashi S, Miki K, Hashizume S, Sugimoto M. Regulation of plaque size and host range by a vaccinia virus gene related to complement system proteins. Virology 1991; 181:158 - 64; http://dx.doi.org/10.1016/0042-6822(91)90480-Y; PMID: 1994573
- Kenner J, Cameron F, Empig C, Jobes DV, Gurwith M. LC16m8: an attenuated smallpox vaccine. Vaccine 2006; 24:7009 - 22; http://dx.doi.org/10.1016/j.vaccine.2006.03.087; PMID: 17052815
- Johnson BF, Kanatani Y, Fujii T, Saito T, Yokote H, Smith GL. Serological responses in humans to the smallpox vaccine LC16m8. J Gen Virol 2011; 92:2405 - 10; http://dx.doi.org/10.1099/vir.0.034207-0; PMID: 21715598
- Hooper JW, Custer DM, Thompson E. Four-gene-combination DNA vaccine protects mice against a lethal vaccinia virus challenge and elicits appropriate antibody responses in nonhuman primates. Virology 2003; 306:181 - 95; http://dx.doi.org/10.1016/S0042-6822(02)00038-7; PMID: 12620810
- Sakhatskyy P, Wang S, Zhang C, Chou TH, Kishko M, Lu S. Immunogenicity and protection efficacy of subunit-based smallpox vaccines using variola major antigens. Virology 2008; 371:98 - 107; http://dx.doi.org/10.1016/j.virol.2007.09.029; PMID: 17950773
- Pulford DJ, Gates A, Bridge SH, Robinson JH, Ulaeto D. Differential efficacy of vaccinia virus envelope proteins administered by DNA immunisation in protection of BALB/c mice from a lethal intranasal poxvirus challenge. Vaccine 2004; 22:3358 - 66; http://dx.doi.org/10.1016/j.vaccine.2004.02.034; PMID: 15308360
- Hirao LA, Draghia-Akli R, Prigge JT, Yang M, Satishchandran A, Wu L, et al. Multivalent smallpox DNA vaccine delivered by intradermal electroporation drives protective immunity in nonhuman primates against lethal monkeypox challenge. J Infect Dis 2011; 203:95 - 102; http://dx.doi.org/10.1093/infdis/jiq017; PMID: 21148501
- Fogg C, Lustig S, Whitbeck JC, Eisenberg RJ, Cohen GH, Moss B. Protective immunity to vaccinia virus induced by vaccination with multiple recombinant outer membrane proteins of intracellular and extracellular virions. J Virol 2004; 78:10230 - 7; http://dx.doi.org/10.1128/JVI.78.19.10230-10237.2004; PMID: 15367588
- Davies DH, McCausland MM, Valdez C, Huynh D, Hernandez JE, Mu Y, et al. Vaccinia virus H3L envelope protein is a major target of neutralizing antibodies in humans and elicits protection against lethal challenge in mice. J Virol 2005; 79:11724 - 33; http://dx.doi.org/10.1128/JVI.79.18.11724-11733.2005; PMID: 16140750
- Buchman GW, Cohen ME, Xiao Y, Richardson-Harman N, Silvera P, DeTolla LJ, et al. A protein-based smallpox vaccine protects non-human primates from a lethal monkeypox virus challenge. Vaccine 2010; 28:6627 - 36; http://dx.doi.org/10.1016/j.vaccine.2010.07.030; PMID: 20659519
- Moise L, Buller RM, Schriewer J, Lee J, Frey SE, Weiner DB, et al. VennVax, a DNA-prime, peptide-boost multi-T-cell epitope poxvirus vaccine, induces protective immunity against vaccinia infection by T cell response alone. Vaccine 2011; 29:501 - 11; http://dx.doi.org/10.1016/j.vaccine.2010.10.064; PMID: 21055490
- Moss B. Genetically engineered poxviruses for recombinant gene expression, vaccination, and safety. Proc Natl Acad Sci U S A 1996; 93:11341 - 8; http://dx.doi.org/10.1073/pnas.93.21.11341; PMID: 8876137
- Yilma T. Applications of recombinant vaccinia virus for veterinary vaccines. Dev Biol Stand 1994; 82:201 - 9; PMID: 7958475
- Wiktor TJ, Macfarlan RI, Reagan KJ, Dietzschold B, Curtis PJ, Wunner WH, et al. Protection from rabies by a vaccinia virus recombinant containing the rabies virus glycoprotein gene. Proc Natl Acad Sci U S A 1984; 81:7194 - 8; http://dx.doi.org/10.1073/pnas.81.22.7194; PMID: 6095272
- Kieny MP, Lathe R, Drillien R, Spehner D, Skory S, Schmitt D, et al. Expression of rabies virus glycoprotein from a recombinant vaccinia virus. Nature 1984; 312:163 - 6; http://dx.doi.org/10.1038/312163a0; PMID: 6548799
- Pastoret PP, Brochier B. The development and use of a vaccinia-rabies recombinant oral vaccine for the control of wildlife rabies; a link between Jenner and Pasteur. Epidemiol Infect 1996; 116:235 - 40; http://dx.doi.org/10.1017/S0950268800052535; PMID: 8666066
- Giavedoni L, Jones L, Mebus C, Yilma T. A vaccinia virus double recombinant expressing the F and H genes of rinderpest virus protects cattle against rinderpest and causes no pock lesions. Proc Natl Acad Sci U S A 1991; 88:8011 - 5; http://dx.doi.org/10.1073/pnas.88.18.8011; PMID: 1896447
- Verardi PH, Aziz FH, Ahmad S, Jones LA, Beyene B, Ngotho RN, et al. Long-term sterilizing immunity to rinderpest in cattle vaccinated with a recombinant vaccinia virus expressing high levels of the fusion and hemagglutinin glycoproteins. J Virol 2002; 76:484 - 91; http://dx.doi.org/10.1128/JVI.76.2.484-491.2002; PMID: 11752138
- Gudmundsdotter L, Nilsson C, Brave A, Hejdeman B, Earl P, Moss B, et al. Recombinant Modified Vaccinia Ankara (MVA) effectively boosts DNA-primed HIV-specific immune responses in humans despite pre-existing vaccinia immunity. Vaccine 2009; 27:4468 - 74; http://dx.doi.org/10.1016/j.vaccine.2009.05.018; PMID: 19450644
- Rerks-Ngarm S, Pitisuttithum P, Nitayaphan S, Kaewkungwal J, Chiu J, Paris R, et al, MOPH-TAVEG Investigators. Vaccination with ALVAC and AIDSVAX to prevent HIV-1 infection in Thailand. N Engl J Med 2009; 361:2209 - 20; http://dx.doi.org/10.1056/NEJMoa0908492; PMID: 19843557
- Sheehy SH, Duncan CJ, Elias SC, Biswas S, Collins KA, O’Hara GA, et al. Phase Ia clinical evaluation of the safety and immunogenicity of the Plasmodium falciparum blood-stage antigen AMA1 in ChAd63 and MVA vaccine vectors. PLoS One 2012; 7:e31208; http://dx.doi.org/10.1371/journal.pone.0031208; PMID: 22363582
- Sheehy SH, Duncan CJ, Elias SC, Collins KA, Ewer KJ, Spencer AJ, et al. Phase Ia clinical evaluation of the Plasmodium falciparum blood-stage antigen MSP1 in ChAd63 and MVA vaccine vectors. Mol Ther 2011; 19:2269 - 76; http://dx.doi.org/10.1038/mt.2011.176; PMID: 21862998
- O’Hara GA, Duncan CJ, Ewer KJ, Collins KA, Elias SC, Halstead FD, et al. Clinical assessment of a recombinant simian adenovirus ChAd63: a potent new vaccine vector. J Infect Dis 2012; 205:772 - 81; http://dx.doi.org/10.1093/infdis/jir850; PMID: 22275401
- Scriba TJ, Tameris M, Mansoor N, Smit E, van der Merwe L, Isaacs F, et al. Modified vaccinia Ankara-expressing Ag85A, a novel tuberculosis vaccine, is safe in adolescents and children, and induces polyfunctional CD4+ T cells. Eur J Immunol 2010; 40:279 - 90; http://dx.doi.org/10.1002/eji.200939754; PMID: 20017188
- Youn JW, Hu YW, Tricoche N, Pfahler W, Shata MT, Dreux M, et al. Evidence for protection against chronic hepatitis C virus infection in chimpanzees by immunization with replicating recombinant vaccinia virus. J Virol 2008; 82:10896 - 905; http://dx.doi.org/10.1128/JVI.01179-08; PMID: 18753204
- de Waal L, Wyatt LS, Yüksel S, van Amerongen G, Moss B, Niesters HG, et al. Vaccination of infant macaques with a recombinant modified vaccinia virus Ankara expressing the respiratory syncytial virus F and G genes does not predispose for immunopathology. Vaccine 2004; 22:923 - 6; http://dx.doi.org/10.1016/j.vaccine.2003.10.010; PMID: 15161069
- Merkel TJ, Perera PY, Kelly VK, Verma A, Llewellyn ZN, Waldmann TA, et al. Development of a highly efficacious vaccinia-based dual vaccine against smallpox and anthrax, two important bioterror entities. Proc Natl Acad Sci U S A 2010; 107:18091 - 6; http://dx.doi.org/10.1073/pnas.1013083107; PMID: 20921397
- Guillaume V, Contamin H, Loth P, Georges-Courbot MC, Lefeuvre A, Marianneau P, et al. Nipah virus: vaccination and passive protection studies in a hamster model. J Virol 2004; 78:834 - 40; http://dx.doi.org/10.1128/JVI.78.2.834-840.2004; PMID: 14694115
- Gulley JL, Arlen PM, Madan RA, Tsang KY, Pazdur MP, Skarupa L, et al. Immunologic and prognostic factors associated with overall survival employing a poxviral-based PSA vaccine in metastatic castrate-resistant prostate cancer. Cancer Immunol Immunother 2010; 59:663 - 74; http://dx.doi.org/10.1007/s00262-009-0782-8; PMID: 19890632
- Kantoff PW, Schuetz TJ, Blumenstein BA, Glode LM, Bilhartz DL, Wyand M, et al. Overall survival analysis of a phase II randomized controlled trial of a Poxviral-based PSA-targeted immunotherapy in metastatic castration-resistant prostate cancer. J Clin Oncol 2010; 28:1099 - 105; http://dx.doi.org/10.1200/JCO.2009.25.0597; PMID: 20100959
- National Library of Medicine (US). ClinicalTrials.gov [Internet]. Bethesda (MD), 2000- (accessed 2012 June 1).
- Rountree RB, Mandl SJ, Nachtwey JM, Dalpozzo K, Do L, Lombardo JR, et al. Exosome targeting of tumor antigens expressed by cancer vaccines can improve antigen immunogenicity and therapeutic efficacy. Cancer Res 2011; 71:5235 - 44; http://dx.doi.org/10.1158/0008-5472.CAN-10-4076; PMID: 21670078
- Mandl SJ, Rountree RB, Dalpozzo K, Do L, Lombardo JR, Schoonmaker PL, et al. Immunotherapy with MVA-BN®-HER2 induces HER-2-specific Th1 immunity and alters the intratumoral balance of effector and regulatory T cells. Cancer Immunol Immunother 2012; 61:19 - 29; http://dx.doi.org/10.1007/s00262-011-1077-4; PMID: 21822917
- Harrop R, Drury N, Shingler W, Chikoti P, Redchenko I, Carroll MW, et al. Vaccination of colorectal cancer patients with TroVax given alongside chemotherapy (5-fluorouracil, leukovorin and irinotecan) is safe and induces potent immune responses. Cancer Immunol Immunother 2008; 57:977 - 86; http://dx.doi.org/10.1007/s00262-007-0428-7; PMID: 18060404
- Kaufman HL, Taback B, Sherman W, Kim DW, Shingler WH, Moroziewicz D, et al. Phase II trial of Modified Vaccinia Ankara (MVA) virus expressing 5T4 and high dose Interleukin-2 (IL-2) in patients with metastatic renal cell carcinoma. J Transl Med 2009; 7:2; http://dx.doi.org/10.1186/1479-5876-7-2; PMID: 19128501
- Amato RJ, Hawkins RE, Kaufman HL, Thompson JA, Tomczak P, Szczylik C, et al. Vaccination of metastatic renal cancer patients with MVA-5T4: a randomized, double-blind, placebo-controlled phase III study. Clin Cancer Res 2010; 16:5539 - 47; http://dx.doi.org/10.1158/1078-0432.CCR-10-2082; PMID: 20881001
- Harrop R, Shingler W, Kelleher M, de Belin J, Treasure P. Cross-trial analysis of immunologic and clinical data resulting from phase I and II trials of MVA-5T4 (TroVax) in colorectal, renal, and prostate cancer patients. J Immunother 2010; 33:999 - 1005; http://dx.doi.org/10.1097/CJI.0b013e3181f5dac7; PMID: 20948436
- Harrop R, Shingler WH, McDonald M, Treasure P, Amato RJ, Hawkins RE, et al. MVA-5T4-induced immune responses are an early marker of efficacy in renal cancer patients. Cancer Immunol Immunother 2011; 60:829 - 37; http://dx.doi.org/10.1007/s00262-011-0993-7; PMID: 21387109
- Odunsi K, Matsuzaki J, Karbach J, Neumann A, Mhawech-Fauceglia P, Miller A, et al. Efficacy of vaccination with recombinant vaccinia and fowlpox vectors expressing NY-ESO-1 antigen in ovarian cancer and melanoma patients. Proc Natl Acad Sci U S A 2012; 109:5797 - 802; http://dx.doi.org/10.1073/pnas.1117208109; PMID: 22454499
- Dreicer R, Stadler WM, Ahmann FR, Whiteside T, Bizouarne N, Acres B, et al. MVA-MUC1-IL2 vaccine immunotherapy (TG4010) improves PSA doubling time in patients with prostate cancer with biochemical failure. Invest New Drugs 2009; 27:379 - 86; http://dx.doi.org/10.1007/s10637-008-9187-3; PMID: 18931824
- Quoix E, Ramlau R, Westeel V, Papai Z, Madroszyk A, Riviere A, et al. Therapeutic vaccination with TG4010 and first-line chemotherapy in advanced non-small-cell lung cancer: a controlled phase 2B trial. Lancet Oncol 2011; 12:1125 - 33; http://dx.doi.org/10.1016/S1470-2045(11)70259-5; PMID: 22019520
- Mohebtash M, Tsang KY, Madan RA, Huen NY, Poole DJ, Jochems C, et al. A pilot study of MUC-1/CEA/TRICOM poxviral-based vaccine in patients with metastatic breast and ovarian cancer. Clin Cancer Res 2011; 17:7164 - 73; http://dx.doi.org/10.1158/1078-0432.CCR-11-0649; PMID: 22068656
- Kirn DH, Thorne SH. Targeted and armed oncolytic poxviruses: a novel multi-mechanistic therapeutic class for cancer. Nat Rev Cancer 2009; 9:64 - 71; http://dx.doi.org/10.1038/nrc2545; PMID: 19104515
- McCart JA, Ward JM, Lee J, Hu Y, Alexander HR, Libutti SK, et al. Systemic cancer therapy with a tumor-selective vaccinia virus mutant lacking thymidine kinase and vaccinia growth factor genes. Cancer Res 2001; 61:8751 - 7; PMID: 11751395
- Puhlmann M, Brown CK, Gnant M, Huang J, Libutti SK, Alexander HR, et al. Vaccinia as a vector for tumor-directed gene therapy: biodistribution of a thymidine kinase-deleted mutant. Cancer Gene Ther 2000; 7:66 - 73; http://dx.doi.org/10.1038/sj.cgt.7700075; PMID: 10678358
- Liu TC, Hwang T, Park BH, Bell J, Kirn DH. The targeted oncolytic poxvirus JX-594 demonstrates antitumoral, antivascular, and anti-HBV activities in patients with hepatocellular carcinoma. Mol Ther 2008; 16:1637 - 42; http://dx.doi.org/10.1038/mt.2008.143; PMID: 18628758
- Park BH, Hwang T, Liu TC, Sze DY, Kim JS, Kwon HC, et al. Use of a targeted oncolytic poxvirus, JX-594, in patients with refractory primary or metastatic liver cancer: a phase I trial. Lancet Oncol 2008; 9:533 - 42; http://dx.doi.org/10.1016/S1470-2045(08)70107-4; PMID: 18495536
- Hwang TH, Moon A, Burke J, Ribas A, Stephenson J, Breitbach CJ, et al. A mechanistic proof-of-concept clinical trial with JX-594, a targeted multi-mechanistic oncolytic poxvirus, in patients with metastatic melanoma. Mol Ther 2011; 19:1913 - 22; http://dx.doi.org/10.1038/mt.2011.132; PMID: 21772252
- McCart JA, Mehta N, Scollard D, Reilly RM, Carrasquillo JA, Tang N, et al. Oncolytic vaccinia virus expressing the human somatostatin receptor SSTR2: molecular imaging after systemic delivery using 111In-pentetreotide. Mol Ther 2004; 10:553 - 61; http://dx.doi.org/10.1016/j.ymthe.2004.06.158; PMID: 15336655
- Chalikonda S, Kivlen MH, O’Malley ME, Eric Dong XD, McCart JA, Gorry MC, et al. Oncolytic virotherapy for ovarian carcinomatosis using a replication-selective vaccinia virus armed with a yeast cytosine deaminase gene. Cancer Gene Ther 2008; 15:115 - 25; http://dx.doi.org/10.1038/sj.cgt.7701110; PMID: 18084242
- Zhang Q, Yu YA, Wang E, Chen N, Danner RL, Munson PJ, et al. Eradication of solid human breast tumors in nude mice with an intravenously injected light-emitting oncolytic vaccinia virus. Cancer Res 2007; 67:10038 - 46; http://dx.doi.org/10.1158/0008-5472.CAN-07-0146; PMID: 17942938
- Gentschev I, Adelfinger M, Josupeit R, Rudolph S, Ehrig K, Donat U, et al. Preclinical evaluation of oncolytic vaccinia virus for therapy of canine soft tissue sarcoma. PLoS One 2012; 7:e37239; http://dx.doi.org/10.1371/journal.pone.0037239; PMID: 22615950
- Yu YA, Galanis C, Woo Y, Chen N, Zhang Q, Fong Y, et al. Regression of human pancreatic tumor xenografts in mice after a single systemic injection of recombinant vaccinia virus GLV-1h68. Mol Cancer Ther 2009; 8:141 - 51; http://dx.doi.org/10.1158/1535-7163.MCT-08-0533; PMID: 19139123
- Yu YA, Timiryasova T, Zhang Q, Beltz R, Szalay AA. Optical imaging: bacteria, viruses, and mammalian cells encoding light-emitting proteins reveal the locations of primary tumors and metastases in animals. Anal Bioanal Chem 2003; 377:964 - 72; http://dx.doi.org/10.1007/s00216-003-2065-0; PMID: 12879198
- Plotke F, Lazowski ES. Comparative Results of Smallpox Revaccination Using Regular and Dry Smallpox Vaccine (Dryvax). IMJ Ill Med J 1964; 125:140 - 1; PMID: 14121126
- Jones L, Giavedoni L, Saliki JT, Brown C, Mebus C, Yilma T. Protection of goats against peste des petits ruminants with a vaccinia virus double recombinant expressing the F and H genes of rinderpest virus. Vaccine 1993; 11:961 - 4; http://dx.doi.org/10.1016/0264-410X(93)90386-C; PMID: 8212844
- Mackett M, Yilma T, Rose JK, Moss B. Vaccinia virus recombinants: expression of VSV genes and protective immunization of mice and cattle. Science 1985; 227:433 - 5; http://dx.doi.org/10.1126/science.2981435; PMID: 2981435
- Meulemans G, Letellier C, Gonze M, Carlier MC, Burny A. Newcastle disease virus F glycoprotein expressed from a recombinant vaccinia virus vector protects chickens against live-virus challenge. Avian Pathol 1988; 17:821 - 7; http://dx.doi.org/10.1080/03079458808436504; PMID: 18766743
- Espion D, de Henau S, Letellier C, Wemers CD, Brasseur R, Young JF, et al. Expression at the cell surface of native fusion protein of the Newcastle disease virus (NDV) strain Italien from cloned cDNA. Arch Virol 1987; 95:79 - 95; http://dx.doi.org/10.1007/BF01311336; PMID: 3592986
- Carson C, Antoniou M, Ruiz-Argüello MB, Alcami A, Christodoulou V, Messaritakis I, et al. A prime/boost DNA/Modified vaccinia virus Ankara vaccine expressing recombinant Leishmania DNA encoding TRYP is safe and immunogenic in outbred dogs, the reservoir of zoonotic visceral leishmaniasis. Vaccine 2009; 27:1080 - 6; http://dx.doi.org/10.1016/j.vaccine.2008.11.094; PMID: 19095029
- Taylor J, Pincus S, Tartaglia J, Richardson C, Alkhatib G, Briedis D, et al. Vaccinia virus recombinants expressing either the measles virus fusion or hemagglutinin glycoprotein protect dogs against canine distemper virus challenge. J Virol 1991; 65:4263 - 74; PMID: 1830113
- Cross ML, Fleming SB, Cowan PE, Scobie S, Whelan E, Prada D, et al. Vaccinia virus as a vaccine delivery system for marsupial wildlife. Vaccine 2011; 29:4537 - 43; http://dx.doi.org/10.1016/j.vaccine.2011.04.093; PMID: 21570435
- Papin JF, Verardi PH, Jones LA, Monge-Navarro F, Brault AC, Holbrook MR, et al. Recombinant Rift Valley fever vaccines induce protective levels of antibody in baboons and resistance to lethal challenge in mice. Proc Natl Acad Sci U S A 2011; 108:14926 - 31; http://dx.doi.org/10.1073/pnas.1112149108; PMID: 21873194
- Bakari M, Aboud S, Nilsson C, Francis J, Buma D, Moshiro C, et al. Broad and potent immune responses to a low dose intradermal HIV-1 DNA boosted with HIV-1 recombinant MVA among healthy adults in Tanzania. Vaccine 2011; 29:8417 - 28; http://dx.doi.org/10.1016/j.vaccine.2011.08.001; PMID: 21864626
- Bart PA, Goodall R, Barber T, Harari A, Guimaraes-Walker A, Khonkarly M, et al, EuroVacc Consortium. EV01: a phase I trial in healthy HIV negative volunteers to evaluate a clade C HIV vaccine, NYVAC-C undertaken by the EuroVacc Consortium. Vaccine 2008; 26:3153 - 61; http://dx.doi.org/10.1016/j.vaccine.2008.03.083; PMID: 18502002
- McCormack S, Stöhr W, Barber T, Bart PA, Harari A, Moog C, et al. EV02: a Phase I trial to compare the safety and immunogenicity of HIV DNA-C prime-NYVAC-C boost to NYVAC-C alone. Vaccine 2008; 26:3162 - 74; http://dx.doi.org/10.1016/j.vaccine.2008.02.072; PMID: 18502003
- Harari A, Bart PA, Stöhr W, Tapia G, Garcia M, Medjitna-Rais E, et al. An HIV-1 clade C DNA prime, NYVAC boost vaccine regimen induces reliable, polyfunctional, and long-lasting T cell responses. J Exp Med 2008; 205:63 - 77; http://dx.doi.org/10.1084/jem.20071331; PMID: 18195071
- García F, Bernaldo de Quirós JC, Gómez CE, Perdiguero B, Nájera JL, Jiménez V, et al. Safety and immunogenicity of a modified pox vector-based HIV/AIDS vaccine candidate expressing Env, Gag, Pol and Nef proteins of HIV-1 subtype B (MVA-B) in healthy HIV-1-uninfected volunteers: A phase I clinical trial (RISVAC02). Vaccine 2011; 29:8309 - 16; http://dx.doi.org/10.1016/j.vaccine.2011.08.098; PMID: 21907749
- Goepfert PA, Elizaga ML, Sato A, Qin L, Cardinali M, Hay CM, et al, National Institute of Allergy and Infectious Diseases HIV Vaccine Trials Network. Phase 1 safety and immunogenicity testing of DNA and recombinant modified vaccinia Ankara vaccines expressing HIV-1 virus-like particles. J Infect Dis 2011; 203:610 - 9; http://dx.doi.org/10.1093/infdis/jiq105; PMID: 21282192
- Berthoud TK, Hamill M, Lillie PJ, Hwenda L, Collins KA, Ewer KJ, et al. Potent CD8+ T-cell immunogenicity in humans of a novel heterosubtypic influenza A vaccine, MVA-NP+M1. Clin Infect Dis 2011; 52:1 - 7; http://dx.doi.org/10.1093/cid/ciq015; PMID: 21148512
- Cavenaugh JS, Awi D, Mendy M, Hill AV, Whittle H, McConkey SJ. Partially randomized, non-blinded trial of DNA and MVA therapeutic vaccines based on hepatitis B virus surface protein for chronic HBV infection. PLoS One 2011; 6:e14626; http://dx.doi.org/10.1371/journal.pone.0014626; PMID: 21347224