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Sezgin E, An P, Winkler CA. Host Genetics of Cytomegalovirus Pathogenesis. Front Genet 2019; 10:616. [PMID: 31396258 PMCID: PMC6664682 DOI: 10.3389/fgene.2019.00616] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 06/13/2019] [Indexed: 12/12/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous herpes virus (human herpes virus 5) with the highest morbidity and mortality rates compared to other herpes viruses. Risk groups include very young, elderly, transplant recipient, and immunocompromised individuals. HCMV may cause retinitis, encephalitis, hepatitis, esophagitis, colitis, pneumonia, neonatal infection sequelae, inflammatory, and age-related diseases. With an arsenal of genes in its large genome dedicated to host immune evasion, HCMV can block intrinsic cellular defenses and interfere with cellular immune responses. HCMV also encodes chemokines, chemokine receptors, and cytokines. Therefore, genes involved in human viral defense mechanisms and those encoding proteins targeted by the CMV proteins are candidates for host control of CMV infection and reactivation. Although still few in number, host genetic studies are producing valuable insights into biological processes involved in HCMV pathogenesis and HCMV-related diseases. For example, genetic variants in the immunoglobulin GM light chain can influence the antibody responsiveness to CMV glycoprotein B and modify risk of HCMV-related diseases. Moreover, CMV infection following organ transplantation has been associated with variants in genes encoding toll-like receptors (TLRs), programmed death-1 (PD-1), and interleukin-12p40 (IL-12B). A KIR haplotype (2DS4+) is proposed to be protective for CMV activation among hematopoietic stem cell transplant patients. Polymorphisms in the interferon lambda 3/4 (IFNL3/4) region are shown to influence susceptibility to CMV replication among solid organ transplant patients. Interestingly, the IFNL3/4 region is also associated with AIDS-related CMV retinitis susceptibility in HIV-infected patients. Likewise, interleukin-10 receptor 1 (IL-10R1) variants are shown to influence CMV retinitis development in patients with AIDS. Results from genome-wide association studies suggest a possible role for microtubule network and retinol metabolism in anti-CMV antibody response. Nevertheless, further genetic epidemiological studies with large cohorts, functional studies on the numerous HCMV genes, and immune response to chronic and latent states of infection that contribute to HCMV persistence are clearly necessary to elucidate the genetic mechanisms of CMV infection, reactivation, and pathogenesis.
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Affiliation(s)
- Efe Sezgin
- Laboratory of Nutrigenomics and Epidemiology, Izmir Institute of Technology, Urla, Turkey
| | - Ping An
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Cheryl A Winkler
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, United States
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Abstract
The development of a cytomegalovirus (CMV) vaccine has become a top priority due to its potential cost-effectiveness and associated public health benefits. However, there are a number of challenges facing vaccine development including the following: (1) CMV has many mechanisms for evading immune responses , and natural immunity is not perfect, (2) the immune correlates for protection are unclear, (3) a narrow range of CMV hosts limits the value of animal models, and (4) the placenta is a specialized organ formed transiently and its immunological status changes with time. In spite of these limitations, several types of CMV vaccine candidate, including live-attenuated, DISC , subunit, DNA, vectored, and peptide vaccines, have been developed or are currently under development. The recognition of the pentameric complex as the major neutralization target and identification of various strategies to block viral immune response evasion mechanisms have opened new avenues to CMV vaccine development. Here, we discuss the immune correlates for protection, the characteristics of the various vaccine candidates and their clinical trials, and the relevant animal models.
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Tomić A, Varanasi PR, Golemac M, Malić S, Riese P, Borst EM, Mischak-Weissinger E, Guzmán CA, Krmpotić A, Jonjić S, Messerle M. Activation of Innate and Adaptive Immunity by a Recombinant Human Cytomegalovirus Strain Expressing an NKG2D Ligand. PLoS Pathog 2016; 12:e1006015. [PMID: 27907183 PMCID: PMC5131914 DOI: 10.1371/journal.ppat.1006015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/21/2016] [Indexed: 12/23/2022] Open
Abstract
Development of an effective vaccine against human cytomegalovirus (HCMV) is a need of utmost medical importance. Generally, it is believed that a live attenuated vaccine would best provide protective immunity against this tenacious pathogen. Here, we propose a strategy for an HCMV vaccine that aims at the simultaneous activation of innate and adaptive immune responses. An HCMV strain expressing the host ligand ULBP2 for the NKG2D receptor was found to be susceptible to control by natural killer (NK) cells, and preserved the ability to stimulate HCMV-specific T cells. Infection with the ULBP2-expressing HCMV strain caused diminished cell surface levels of MHC class I molecules. While expression of the NKG2D ligand increased the cytolytic activity of NK cells, NKG2D engagement in CD8+ T cells provided co-stimulation and compensated for lower MHC class I expression. Altogether, our data indicate that triggering of both arms of the immune system is a promising approach applicable to the generation of a live attenuated HCMV vaccine. Human cytomegalovirus (CMV) is a major cause of morbidity and mortality in congenitally infected newborns and immunocompromised individuals, indicating an utmost need for a vaccine to protect these vulnerable groups. Recent experimental studies in animal models, including non-human primates, have shown that attenuated CMVs trigger a potent immune response and are attractive vaccine candidates. However, an effective CMV vaccine is still not available. Here, we demonstrate that rational engineering of a live attenuated human CMV vaccine candidate is feasible. We equipped a CMV strain with an immunostimulatory molecule that is a ligand for an activating receptor present on both Natural Killer cells and CD8+ T cells. Moreover, we deleted several immunoevasins involved in downregulation of MHC class I molecules and of a ligand for Natural Killer cells in order to elicit stronger immune responses. In vitro assays using human immune cells and a first assessment in a humanized mouse model in vivo suggest that the generated CMV strain is attenuated and has the ability to induce a virus-specific immune response. Our study proposes this novel approach for the development of a rationally engineered CMV vaccine.
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Affiliation(s)
- Adriana Tomić
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Pavankumar R. Varanasi
- Clinics of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Mijo Golemac
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Suzana Malić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Peggy Riese
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Eva M. Borst
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Eva Mischak-Weissinger
- Clinics of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany
| | - Carlos A. Guzmán
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany
| | - Astrid Krmpotić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Stipan Jonjić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- * E-mail: (MM); (SJ)
| | - Martin Messerle
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany
- * E-mail: (MM); (SJ)
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Choi KY, Root M, McGregor A. A Novel Non-Replication-Competent Cytomegalovirus Capsid Mutant Vaccine Strategy Is Effective in Reducing Congenital Infection. J Virol 2016; 90:7902-19. [PMID: 27334585 PMCID: PMC4988156 DOI: 10.1128/jvi.00283-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/17/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Congenital cytomegalovirus (CMV) infection is a leading cause of mental retardation and deafness in newborns. The guinea pig is the only small animal model for congenital CMV infection. A novel CMV vaccine was investigated as an intervention strategy against congenital guinea pig cytomegalovirus (GPCMV) infection. In this disabled infectious single-cycle (DISC) vaccine strategy, a GPCMV mutant virus was used that lacked the ability to express an essential capsid gene (the UL85 homolog GP85) except when grown on a complementing cell line. In vaccinated animals, the GP85 mutant virus (GP85 DISC) induced an antibody response to important glycoprotein complexes considered neutralizing target antigens (gB, gH/gL/gO, and gM/gN). The vaccine also generated a T cell response to the pp65 homolog (GP83), determined via a newly established guinea pig gamma interferon enzyme-linked immunosorbent spot assay. In a congenital infection protection study, GP85 DISC-vaccinated animals and a nonvaccinated control group were challenged during pregnancy with wild-type GPCMV (10(5) PFU). The pregnant animals carried the pups to term, and viral loads in target organs of pups were analyzed. Based on live pup births in the vaccinated and control groups (94.1% versus 63.6%), the vaccine was successful in reducing mortality (P = 0.0002). Additionally, pups from the vaccinated group had reduced CMV transmission, with 23.5% infected target organs versus 75.9% in the control group. Overall, these preliminary studies indicate that a DISC CMV vaccine strategy has the ability to induce an immune response similar to that of natural virus infection but has the increased safety of a non-replication-competent virus, which makes this approach attractive as a CMV vaccine strategy. IMPORTANCE Congenital CMV infection is a leading cause of mental retardation and deafness in newborns. An effective vaccine against CMV remains an elusive goal despite over 50 years of CMV research. The guinea pig, with a placenta structure similar to that in humans, is the only small animal model for congenital CMV infection and recapitulates disease symptoms (e.g., deafness) in newborn pups. In this report, a novel vaccine strategy against congenital guinea pig cytomegalovirus (GPCMV) infection was developed, characterized, and tested for efficacy. This disabled infectious single-cycle (DISC) vaccine strategy induced a neutralizing antibody or a T cell response to important target antigens. In a congenital infection protection study, animals were protected against CMV in comparison to the nonvaccinated group (52% reduction of transmission). This novel vaccine was more effective than previously tested gB-based vaccines and most other strategies involving live virus vaccines. Overall, the DISC vaccine is a safe and promising approach against congenital CMV infection.
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Affiliation(s)
- K Yeon Choi
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, Texas, USA
| | - Matthew Root
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, Texas, USA
| | - Alistair McGregor
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, Texas, USA
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A Homolog Pentameric Complex Dictates Viral Epithelial Tropism, Pathogenicity and Congenital Infection Rate in Guinea Pig Cytomegalovirus. PLoS Pathog 2016; 12:e1005755. [PMID: 27387220 PMCID: PMC4936736 DOI: 10.1371/journal.ppat.1005755] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/17/2016] [Indexed: 11/19/2022] Open
Abstract
In human cytomegalovirus (HCMV), tropism to epithelial and endothelial cells is dependent upon a pentameric complex (PC). Given the structure of the placenta, the PC is potentially an important neutralizing antibody target antigen against congenital infection. The guinea pig is the only small animal model for congenital CMV. Guinea pig cytomegalovirus (GPCMV) potentially encodes a UL128-131 HCMV PC homolog locus (GP128-GP133). In transient expression studies, GPCMV gH and gL glycoproteins interacted with UL128, UL130 and UL131 homolog proteins (designated GP129 and GP131 and GP133 respectively) to form PC or subcomplexes which were determined by immunoprecipitation reactions directed to gH or gL. A natural GP129 C-terminal deletion mutant (aa 107-179) and a chimeric HCMV UL128 C-terminal domain swap GP129 mutant failed to form PC with other components. GPCMV infection of a newly established guinea pig epithelial cell line required a complete PC and a GP129 mutant virus lacked epithelial tropism and was attenuated in the guinea pig for pathogenicity and had a low congenital transmission rate. Individual knockout of GP131 or 133 genes resulted in loss of viral epithelial tropism. A GP128 mutant virus retained epithelial tropism and GP128 was determined not to be a PC component. A series of GPCMV mutants demonstrated that gO was not strictly essential for epithelial infection whereas gB and the PC were essential. Ectopic expression of a GP129 cDNA in a GP129 mutant virus restored epithelial tropism, pathogenicity and congenital infection. Overall, GPCMV forms a PC similar to HCMV which enables evaluation of PC based vaccine strategies in the guinea pig model.
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Coleman S, Hornig J, Maddux S, Choi KY, McGregor A. Viral Glycoprotein Complex Formation, Essential Function and Immunogenicity in the Guinea Pig Model for Cytomegalovirus. PLoS One 2015; 10:e0135567. [PMID: 26267274 PMCID: PMC4534421 DOI: 10.1371/journal.pone.0135567] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 07/24/2015] [Indexed: 11/19/2022] Open
Abstract
Development of a cytomegalovirus (CMV) vaccine is a major public health priority due to the risk of congenital infection. A key component of a vaccine is thought to be an effective neutralizing antibody response against the viral glycoproteins necessary for cell entry. Species specificity of human CMV (HCMV) precludes direct studies in an animal model. The guinea pig is the only small animal model for congenital cytomegalovirus infection. Analysis of the guinea pig CMV (GPCMV) genome indicates that it potentially encodes homologs to the HCMV glycoproteins (including gB, gH, gL, gM, gN and gO) that form various cell entry complexes on the outside of the virus: gCI (gB); gCII (gH/gL/gO); gCIII (gM/gN). The gB homolog (GP55) has been investigated as a candidate subunit vaccine but little is known about the other homolog proteins. GPCMV glycoproteins were investigated by transient expression studies which indicated that homolog glycoproteins to gN and gM, or gH, gL and gO were able to co-localize in cells and generate respective homolog complexes which could be verified by immunoprecipitation assays. ELISA studies demonstrated that the individual complexes were highly immunogenic in guinea pigs. The gO (GP74) homolog protein has 13 conserved N-glycosylation sites found in HCMV gO. In transient expression studies, only the glycosylated protein is detected but in virus infected cells both N-glycosylated and non-glycosylated gO protein were detected. In protein interaction studies, a mutant gO that lacked N-glycosylation sites had no impact on the ability of the protein to interact with gH/gL which indicated a potential alternative function associated with these sites. Knockout GPCMV BAC mutagenesis of the respective glycoprotein genes (GP55 for gB, GP75 for gH, GP115 for gL, GP100 for gM, GP73 for gN and GP74 for gO) in separate reactions was lethal for virus regeneration on fibroblast cells which demonstrated the essential nature of the GPCMV glycoproteins. The gene knockout results were similar to HCMV, except in the case of the gO homolog, which was non-essential in epithelial tropic virus but essential in lab adapted GPCMV. Overall, the findings demonstrate the similarity between HCMV and GPCMV glycoproteins and strengthen the relevance of this model for development of CMV intervention strategies.
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Affiliation(s)
- Stewart Coleman
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States of America
| | - Julia Hornig
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States of America
| | - Sarah Maddux
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States of America
| | - K. Yeon Choi
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States of America
| | - Alistair McGregor
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States of America
- * E-mail:
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Herr W, Plachter B. Cytomegalovirus and varicella–zoster virus vaccines in hematopoietic stem cell transplantation. Expert Rev Vaccines 2014; 8:999-1021. [DOI: 10.1586/erv.09.58] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Schleiss MR. Developing a Vaccine against Congenital Cytomegalovirus (CMV) Infection: What Have We Learned from Animal Models? Where Should We Go Next? Future Virol 2013; 8:1161-1182. [PMID: 24523827 DOI: 10.2217/fvl.13.106] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Congenital human cytomegalovirus (HCMV) infection can lead to long-term neurodevelopmental sequelae, including mental retardation and sensorineural hearing loss. Unfortunately, CMVs are highly adapted to their specific species, precluding the evaluation of HCMV vaccines in animal models prior to clinical trials. Several species-specific CMVs have been characterized and developed in models of pathogenesis and vaccine-mediated protection against disease. These include the murine CMV (MCMV), the porcine CMV (PCMV), the rhesus macaque CMV (RhCMV), the rat CMV (RCMV), and the guinea pig CMV (GPCMV). Because of the propensity of the GPCMV to cross the placenta, infecting the fetus in utero, it has emerged as a model of particular interest in studying vaccine-mediated protection of the fetus. In this paper, a review of these various models, with particular emphasis on the value of the model in the testing and evaluation of vaccines against congenital CMV, is provided. Recent exciting developments and advances in these various models are summarized, and recommendations offered for high-priority areas for future study.
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Affiliation(s)
- Mark R Schleiss
- University of Minnesota Medical School Center for Infectious Diseases and Microbiology Translational Research Department of Pediatrics Division of Pediatric Infectious Diseases and Immunology 2001 6 Street SE Minneapolis, MN 55455-3007
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Korsholm KS, Andersen PL, Christensen D. Cationic liposomal vaccine adjuvants in animal challenge models: overview and current clinical status. Expert Rev Vaccines 2012; 11:561-77. [PMID: 22827242 DOI: 10.1586/erv.12.22] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cationic liposome formulations can function as efficient vaccine adjuvants. However, due to the highly diverse nature of lipids, cationic liposomes have different physical-chemical characteristics that influence their adjuvant mechanisms and their relevance for use in different vaccines. These characteristics can be further manipulated by incorporation of additional lipids or stabilizers, and inclusion of carefully selected immunostimulators is a feasible strategy when tailoring cationic liposomal adjuvants for specific disease targets. Thus, cationic liposomes present a plasticity, which makes them promising adjuvants for future vaccines. This versatility has also led to a vast amount of literature on different experimental liposomal formulations in combination with a wide range of immunostimulators. Here, we have compiled information about the animal challenge models and administration routes that have been used to study vaccine adjuvants based on cationic liposomes and provide an overview of the applicability, progress and clinical status of cationic liposomal vaccine adjuvants.
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Affiliation(s)
- Karen Smith Korsholm
- Statens Serum Institut, Department of Infectious Disease Immunology, Artillerivej 5, DK-2300 Copenhagen, Denmark.
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Schuenadel L, Tischer BK, Nitsche A. Generation and characterization of a Cowpox virus mutant lacking host range factor CP77. Virus Res 2012; 168:23-32. [PMID: 22705200 DOI: 10.1016/j.virusres.2012.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 06/05/2012] [Accepted: 06/05/2012] [Indexed: 11/27/2022]
Abstract
Cowpox virus (CPXV) host range factor CP77 was identified to be required for virus replication in Chinese hamster ovary (CHO) cells, but the underlying molecular mechanism by which CP77 modulates host range has remained unclear. Therefore, a CPXVΔCP77 deletion mutant was constructed by applying bacterial artificial chromosome (BAC) technology. Integrity of BAC-derived viral DNA was confirmed by whole genome sequencing. In vitro growth characteristics of CPXV wild type (WT), BAC-derived vCPXV WT and vCPXVΔCP77 were virtually indistinguishable in HEK293T cells, whereas in CHO-K1 cells replication of virus lacking CP77 was unambiguously attenuated. This block of viral replication was confirmed by lack of late viral protein expression. The replication defect of various Orthopoxviruses lacking CP77 in CHO cells could be restored by recombinant expression of CP77. Thus, for the first time, the described CP77-dependent host range effect in CHO cells was shown in the background of CPXV as well as Camelpox virus. To further characterize the mutant virus, cells of several different species were comparably infected with vCPXV WT and vCPXVΔCP77, respectively. Interestingly, except for CHO-K1 cells, vCPXV WT and vCPXVΔCP77 showed no significant difference in terms of morphology of cytopathic effects, expression of a late transcribed virus-encoded green fluorescent protein and virus reproduction, even in other hamster-derived cells. Additionally, in ovo inoculation with either virus revealed the same red-pock phenotype on chicken egg chorioallantoic membranes. Since the data presented indicate a CP77-dependent host range effect only for CHO cells, we conclude that the protein might mediate additional functions not identified yet. The vCPXVΔCP77 deletion mutant generated can now be applied as a useful tool to investigate the function of the putative host range protein CP77.
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Affiliation(s)
- Livia Schuenadel
- Robert Koch-Institut, Zentrum für Biologische Sicherheit 1, Nordufer 20, 13353 Berlin, Germany
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Abstract
The article reviews the history, present status and the future of BT vaccines in Europe. So far, an attenuated (modified live viruses, MLV) and inactivated virus vaccines against BT were developed and used in the field. Moreover, the virus-like particles (VLPs) produced from recombinant baculovirus, and live recombinant vaccinia or canarypox virus-vectored vaccines were tested in the laboratory. The main aims of BT vaccination strategy are: to prevent clinical disease, to reduce the spread of the BTV in the environment and to protect movement of susceptible animals between affected and free zones. Actually, all of the most recent European BT vaccination campaigns have used exclusively inactivated vaccines. The use of inactivated vaccines avoid risk associated with the use of live-attenuated vaccines, such as reversion to virulence, reassortment of genes with field strain, teratogenicity and insufficient attenuation leading to clinical disease. The mass vaccinations of all susceptible animals are the most efficient veterinary method to fight against BT and successful control of disease. The vaccination of livestock has had a major role in reducing BTV circulation and even in eradicating the virus from most areas of Europe.
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Herpesvirus BACs: past, present, and future. J Biomed Biotechnol 2010; 2011:124595. [PMID: 21048927 PMCID: PMC2965428 DOI: 10.1155/2011/124595] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 08/19/2010] [Indexed: 12/12/2022] Open
Abstract
The herpesviridae are a large family of DNA viruses with large and complicated genomes. Genetic manipulation and the generation of recombinant viruses have been extremely difficult. However, herpesvirus bacterial artificial chromosomes (BACs) that were developed approximately 10 years ago have become useful and powerful genetic tools for generating recombinant viruses to study the biology and pathogenesis of herpesviruses. For example, BAC-directed deletion mutants are commonly used to determine the function and essentiality of viral genes. In this paper, we discuss the creation of herpesvirus BACs, functional analyses of herpesvirus mutants, and future applications for studies of herpesviruses. We describe commonly used methods to create and mutate herpesvirus BACs (such as site-directed mutagenesis and transposon mutagenesis). We also evaluate the potential future uses of viral BACs, including vaccine development and gene therapy.
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Abstract
Once thought largely restricted to India and Africa, the insect-borne livestock pathogen Bluetongue virus is now present on every continent with the exception of Antarctica. Outbreaks of the disease caused by the virus in Europe over the last decade, and the resulting impact on trade and agriculture, have focussed attention on the production of safe and effective vaccines. The determinants of protection for bluetongue are well defined but the variability of the virus, which exists as 24 immunologically distinct serotypes, means that even regions where large numbers of animals have been vaccinated remain at risk from new outbreaks of the virus.
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Affiliation(s)
- R Noad
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, United Kingdom
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A live guinea pig cytomegalovirus vaccine deleted of three putative immune evasion genes is highly attenuated but remains immunogenic in a vaccine/challenge model of congenital cytomegalovirus infection. Vaccine 2009; 27:4209-18. [PMID: 19389443 DOI: 10.1016/j.vaccine.2009.04.036] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 04/09/2009] [Accepted: 04/13/2009] [Indexed: 12/29/2022]
Abstract
Live attenuated vaccines for prevention of congenital cytomegalovirus infections encode numerous immune evasion genes. Their removal could potentially improve vaccine safety and efficacy. To test this hypothesis, three genes encoding MHC class I homologs (presumed NK evasins) were deleted from the guinea pig cytomegalovirus genome and the resulting virus, 3DX, was evaluated as a live attenuated vaccine in the guinea pig congenital infection model. 3DX was attenuated in vivo but not in vitro. Vaccination with 3DX produced elevated cytokine levels and higher antibody titers than wild type (WT) virus while avidity and neutralizing titers were similar. Protection, assessed by maternal viral loads and pup mortality following pathogenic viral challenge during pregnancy, was comparable between 3DX and WT and significant compared to naïve animals. These results suggest that the safety and perhaps efficacy of live attenuated human cytomegalovirus vaccines could be enhanced by deletion of viral immunomodulatory genes.
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Systematic review: cytomegalovirus infection in inflammatory bowel disease. J Gastroenterol 2009; 43:735-40. [PMID: 18958541 DOI: 10.1007/s00535-008-2246-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 07/01/2008] [Indexed: 02/04/2023]
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Immunobiology of human cytomegalovirus: from bench to bedside. Clin Microbiol Rev 2009; 22:76-98, Table of Contents. [PMID: 19136435 DOI: 10.1128/cmr.00034-08] [Citation(s) in RCA: 469] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
SUMMARY Following primary infection, human cytomegalovirus (HCMV) establishes lifelong latency and periodically reactivates without causing symptoms in healthy individuals. In the absence of an adequate host-derived immune response, this fine balance of permitting viral reactivation without causing pathogenesis is disrupted, and HCMV can subsequently cause invasive disease and an array of damaging indirect immunological effects. Over the last decade, our knowledge of the immune response to HCMV infection in healthy virus carriers and diseased individuals has allowed us to translate these findings to develop better diagnostic tools and therapeutic strategies. The application of these emerging technologies in the clinical setting is likely to provide opportunities for better management of patients with HCMV-associated diseases.
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Jacobson MA, Adler SP, Sinclair E, Black D, Smith A, Chu A, Moss RB, Wloch MK. A CMV DNA vaccine primes for memory immune responses to live-attenuated CMV (Towne strain). Vaccine 2009; 27:1540-8. [PMID: 19168107 DOI: 10.1016/j.vaccine.2009.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Revised: 12/18/2008] [Accepted: 01/05/2009] [Indexed: 01/06/2023]
Abstract
CMV-seronegative subjects vaccinated intramuscularly or intradermally with a DNA vaccine encoding pp65, IE1, and gB were administered live-attenuated CMV (Towne) to characterize immune priming by the DNA vaccine. CMV-specific memory T-cells (detected by standard ELISPOT assay in only 20% of subjects) were detected by IFN-gamma cultured ELISPOT assay in 60% of subjects primed intramuscularly and correlated with immune responses after Towne. The median time to first pp65 T-cell and gB antibody response after Towne was 14 days for DNA-primed subjects vs. 28 days for controls administered Towne only (p=0.02 and 0.03, respectively). Furthermore, there was a trend toward more DNA-vaccinated subjects than controls developing a gB-specific IFN-gamma T-cell response after Towne administration (47% vs. 0%, p=0.06).
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Affiliation(s)
- Mark A Jacobson
- Positive Health Program, Department of Medicine, University of California San Francisco, 4th Floor, 995 Potrero, San Francisco, CA 94110, United States.
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18
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Nozawa N, Yamamoto Y, Fukui Y, Katano H, Tsutsui Y, Sato Y, Yamada S, Inami Y, Nakamura K, Yokoi M, Kurane I, Inoue N. Identification of a 1.6 kb genome locus of guinea pig cytomegalovirus required for efficient viral growth in animals but not in cell culture. Virology 2008; 379:45-54. [PMID: 18656220 DOI: 10.1016/j.virol.2008.06.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 03/10/2008] [Accepted: 06/10/2008] [Indexed: 11/17/2022]
Abstract
Guinea pig cytomegalovirus (GPCMV) provides a useful model for studies of congenital CMV infection. During characterization of the GPCMV genome sequence, we identified two types of strains in a virus stock purchased from ATCC. One of them, GPCMV/del, lacks a 1.6 kb locus that positionally corresponds to murine CMV (MCMV) M129-M133. Growth of GPCMV/del in cell culture was marginally better than that of the other strain, GPCMV/full, which harbors the 1.6 kb locus. However, in animals infected intraperitoneally with virus stocks containing both strains, GPCMV/full disseminated more efficiently than GPCMV/del, including 200-fold greater viral load in salivary glands. Viral DNA, transcripts of the immediate-early 2 gene homolog, and viral antigens were more abundant in animals infected with GPCMV/full than in those infected with GPCMV/del. Although the observed phenomena have some similarity with the growth properties of MCMV strains defective in mck-1/mck-2(M129/131) and those defective in sgg(M132), no M129-M132 homologs were found in the 1.6 kb locus. Since one of the ORFs in the locus has a weak sequence similarity with HCMV UL130, which relates to cell tropism, further studies will be required to learn the mechanism for efficient GPCMV growth in animal.
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Affiliation(s)
- Naoki Nozawa
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
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19
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Improved HIV-1 specific T-cell responses by short-interval DNA tattooing as compared to intramuscular immunization in non-human primates. Vaccine 2008; 26:3346-51. [PMID: 18467010 DOI: 10.1016/j.vaccine.2008.03.091] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 03/18/2008] [Accepted: 03/24/2008] [Indexed: 11/24/2022]
Abstract
The new intradermal DNA delivery technique, termed DNA tattooing might overcome the discrepancy between the encouraging immunogenicity results obtained with DNA vaccines in murine studies and the poor results obtained in non-human primates and humans, the so called "simian barrier". Here, we demonstrate a 10- to 100-fold increase in the magnitude of vaccine specific T-cell responses in peripheral blood from DNA tattooed rhesus macaques, as compared to T-cell responses in animals immunized via intramuscular (IM) route. A marked increase in the magnitude of the antigen specific T-cell responses as well as an increase in the number of animals responding to the immunogens was observed. These findings in non-human primates suggest that similar results may be observed in humans. Clinical trials are planned to validate tattooing as an optimal method of DNA vaccine delivery in humans.
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20
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Schleiss MR. Cytomegalovirus vaccine strategies. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.18.4.375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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21
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Cui X, McGregor A, Schleiss MR, McVoy MA. Cloning the complete guinea pig cytomegalovirus genome as an infectious bacterial artificial chromosome with excisable origin of replication. J Virol Methods 2008; 149:231-9. [PMID: 18359520 DOI: 10.1016/j.jviromet.2008.01.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 01/25/2008] [Accepted: 01/31/2008] [Indexed: 01/05/2023]
Abstract
Congenital human cytomegalovirus infections are the major infectious cause of birth defects in the United States. How this virus crosses the placenta and causes fetal disease is poorly understood. Guinea pig cytomegalovirus (GPCMV) is a related virus that provides an important model for studying cytomegaloviral congenital transmission and pathogenesis. In order to facilitate genetic analysis of GPCMV, the 232kb GPCMV genome was cloned as an infectious bacterial artificial chromosome (BAC). The BAC vector sequences were flanked by LoxP sites to allow efficient excision using Cre recombinase. All initial clones contained spontaneous deletions of viral sequences and reconstituted mutant viruses with impaired growth kinetics in vitro. The deletions in one BAC were repaired using Escherichia coli genetics. The resulting repaired BAC reconstituted a virus with in vitro replication kinetics identical to the wild type parental virus; moreover, its genome was indistinguishable from that of the wild type parental virus by restriction pattern analysis using multiple restriction enzymes. These results suggest that the repaired BAC is an authentic representation of the complete GPCMV genome. It should provide a valuable tool for evaluating the impact of genetic modifications on the safety and efficacy of live attenuated vaccines and for identifying genes important for congenital transmission and fetal disease.
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Affiliation(s)
- Xiaohong Cui
- Department of Pediatrics, Virginia Commonwealth University School of Medicine, P.O. Box 980163, Richmond, VA, 23298-0163, United States
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22
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Expression of the human cytomegalovirus UL97 gene in a chimeric guinea pig cytomegalovirus (GPCMV) results in viable virus with increased susceptibility to ganciclovir and maribavir. Antiviral Res 2008; 78:250-9. [PMID: 18325607 DOI: 10.1016/j.antiviral.2008.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 01/11/2008] [Accepted: 01/14/2008] [Indexed: 11/21/2022]
Abstract
In lieu of a licensed vaccine, antivirals are being considered as an intervention to prevent congenital human cytomegalovirus (HCMV) infection. Ideally, antiviral therapies should undergo pre-clinical evaluation in an animal model prior to human use. Guinea pig cytomegalovirus (GPCMV) is the only small animal model for congenital CMV. However, GPCMV is not susceptible to the most commonly used HCMV antiviral, ganciclovir (GCV), rendering in vivo study of this agent problematic in the guinea pig model. Human cytomegalovirus (HCMV) susceptibility to GCV is linked to the UL97 gene. We hypothesized that GPCMV susceptibility to GCV could be improved by inserting the HCMV (Towne) UL97 gene into the GPCMV genome in place of the homolog, GP97. A chimeric GPCMV (GPCMV::UL97) expressed UL97 protein, and replicated efficiently in cell culture, with kinetics similar to wild-type GPCMV. In contrast, deletion of GP97 resulted in a virus (GPCMVdGP97) that grew poorly in culture. GPCMV::UL97 had substantially improved susceptibility to the inhibitory effects of GCV in comparison to wild-type GPCMV. Additionally, GPCMV::UL97 exhibited improved susceptibility to another antiviral undergoing clinical trials, maribavir (MBV; benzimidazole riboside 1263W94), which also acts through UL97.
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23
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Abstract
Although infection with human cytomegalovirus (HCMV) is ubiquitous and usually asymptomatic, there are individuals at high risk for serious HCMV disease. These include solid organ and hematopoietic stem cell (HSC) transplant patients, individuals with HIV infection, and the fetus. Since immunity to HCMV ameliorates the severity of disease, there have been efforts made for over 30 years to develop vaccines for use in these high-risk settings. However, in spite of these efforts, no HCMV vaccine appears to be approaching imminent licensure. The reasons for the failure to achieve the goal of a licensed HCMV vaccine are complex, but several key problems stand out. First, the host immune correlates of protective immunity are not yet clear. Secondly, the viral proteins that should be included in a HCMV vaccine are uncertain. Third, clinical trials have largely focused on immunocompromised patients, a population that may not be relevant to the problem of protection of the fetus against congenital infection. Fourth, the ultimate target population for HCMV vaccination remains unclear. Finally, and most importantly, there has been insufficient education about the problem of HCMV infection, particularly among women of child-bearing age and in the lay public. This review considers the strategies that have been explored to date in development of HCMV vaccines, and summarizes both active clinical trials as well as novel technologies that merit future consideration toward the goal of prevention of this significant public health problem.
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Affiliation(s)
- M R Schleiss
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, 2001 6th Street SE, Minneapolis, MN 55455, USA.
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24
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Schleiss MR. Comparison of vaccine strategies against congenital CMV infection in the guinea pig model. J Clin Virol 2007; 41:224-30. [PMID: 18060834 DOI: 10.1016/j.jcv.2007.10.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 10/03/2007] [Indexed: 12/01/2022]
Abstract
Vaccines are urgently needed to protect newborns against the devastating sequelae of congenital cytomegalovirus infection. Evaluation of candidate vaccines in the guinea pig model of congenital infection can shed light on potentially useful strategies for humans, since guinea pig CMV (GPCMV) is transmitted to the fetus transplacentally, causing infection and disease in utero. A number of vaccine strategies have been evaluated in this model, including DNA vaccines, live attenuated vaccines, and recombinant glycoprotein vaccines. Induction of virus-neutralizing antibody appears to play a key role in protection of the fetus. Recently, a vectored vaccine based on the GPCMV homolog of the UL83 (pp65) protein has also been shown to be effective when used as a preconceptual vaccine in this model, suggesting that strategies designed to elicit T-cell responses may be of value in protection of the fetus.
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Affiliation(s)
- Mark R Schleiss
- Division of Pediatric Infectious Diseases and Immunology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, 2001 6th Street SE, Minneapolis, MN 55455, USA.
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25
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Rios SL, Baracho VG, Oliveira KBA, Rizzo PLV. Therapies for human cytomegalovirus. Expert Opin Ther Pat 2007. [DOI: 10.1517/13543776.17.4.407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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26
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Wang Z, La Rosa C, Li Z, Ly H, Krishnan A, Martinez J, Britt WJ, Diamond D. Vaccine properties of a novel marker gene-free recombinant modified vaccinia Ankara expressing immunodominant CMV antigens pp65 and IE1. Vaccine 2007; 25:1132-41. [PMID: 17049414 PMCID: PMC1852509 DOI: 10.1016/j.vaccine.2006.09.067] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 08/17/2006] [Accepted: 09/13/2006] [Indexed: 11/21/2022]
Abstract
CMV tegument protein pp65 and CMV immediate early gene product IE1 are both considered immunodominant targets of cell-mediated immunity (CMI) and potentially capable of controlling CMV infection. To better assess their role in host defense, we have constructed a novel MVA transfer vector named pZWIIA and generated a recombinant MVA (rMVA) expressing both full-length pp65 and exon4 of IE1 (pp65-IE1-MVA) at high levels, followed by the genetic removal of the bacterial marker gene used to distinguish recombinant forms. Immunogenicity evaluation indicates that pp65-IE1-MVA not only can induce robust primary CMI to both antigens in HLA A2.1 Tg mice, but also can stimulate vigorous expansion of memory T lymphocyte responses to pp65 and IE1 in PBMC of CMV-positive donors. These properties make the MVA-based vaccine ideal for the dual role of priming and boosting CMV-specific T cell immunity as a means to control CMV disease in recipients of hematopoietic cell or solid organ transplantation (HCT or SOT). pZWIIA alone or in combination with other MVA transfer vectors can be used to generate MVA based multiple-antigen vaccine which have application in vaccine development for a wide spectrum of infectious diseases and cancer.
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Affiliation(s)
- Zhongde Wang
- Laboratory of Vaccine Research, Division of Virology, Beckman Research Institute of City of Hope, Duarte, CA 91010
| | - Corinna La Rosa
- Laboratory of Vaccine Research, Division of Virology, Beckman Research Institute of City of Hope, Duarte, CA 91010
| | - Zhongqi Li
- Laboratory of Vaccine Research, Division of Virology, Beckman Research Institute of City of Hope, Duarte, CA 91010
| | - Heang Ly
- Laboratory of Vaccine Research, Division of Virology, Beckman Research Institute of City of Hope, Duarte, CA 91010
| | - Aparna Krishnan
- Laboratory of Vaccine Research, Division of Virology, Beckman Research Institute of City of Hope, Duarte, CA 91010
| | - Joy Martinez
- Laboratory of Vaccine Research, Division of Virology, Beckman Research Institute of City of Hope, Duarte, CA 91010
| | - William J. Britt
- Department of Pediatrics, University of Alabama, Birmingham, Alabama 352333
| | - Don Diamond
- Laboratory of Vaccine Research, Division of Virology, Beckman Research Institute of City of Hope, Duarte, CA 91010
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