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Identification and Characterization of a Small-Molecule Rabies Virus Entry Inhibitor. J Virol 2020; 94:JVI.00321-20. [PMID: 32321812 DOI: 10.1128/jvi.00321-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/13/2020] [Indexed: 12/25/2022] Open
Abstract
Rabies virus (RABV) causes a severe and fatal neurological disease, but morbidity is vaccine preventable and treatable prior to the onset of clinical symptoms. However, immunoglobulin (IgG)-based rabies postexposure prophylaxis (PEP) is expensive, restricting access to life-saving treatment, especially for patients in low-income countries where the clinical need is greatest, and does not confer cross-protection against newly emerging phylogroup II lyssaviruses. Toward identifying a cost-effective replacement for the IgG component of rabies PEP, we developed and implemented a high-throughput screening protocol utilizing a single-cycle RABV reporter strain. A large-scale screen and subsequent direct and orthogonal counterscreens identified a first-in-class direct-acting RABV inhibitor, GRP-60367, with a specificity index (SI) of >100,000. Mechanistic characterization through time-of-addition studies, transient cell-to-cell fusion assays, and chimeric vesicular stomatitis virus (VSV) recombinants expressing the RABV glycoprotein (G) demonstrated that GRP-60367 inhibits entry of a subset of RABV strains. Resistance profiling of the chemotype revealed hot spots in conserved hydrophobic positions of the RABV G protein fusion loop that were confirmed in transient cell-to-cell fusion assays. Transfer of RABV G genes with signature resistance mutations into a recombinant VSV backbone resulted in the recovery of replication-competent virions with low susceptibility to the inhibitor. This work outlines a tangible strategy for mechanistic characterization and resistance profiling of RABV drug candidates and identified a novel, well-behaved molecular probe chemotype that specifically targets the RABV G protein and prevents G-mediated viral entry.IMPORTANCE Rabies PEP depends on anti-RABV IgG, which is expensive and in limited supply in geographical areas with the highest disease burden. Replacing the IgG component with a cost-effective and shelf-stable small-molecule antiviral could address this unmet clinical need by expanding access to life-saving medication. This study has established a robust protocol for high-throughput anti-RABV drug screens and identified a chemically well-behaved, first-in-class hit with nanomolar anti-RABV potency that blocks RABV G protein-mediated viral entry. Resistance mapping revealed a druggable site formed by the G protein fusion loops that has not previously emerged as a target for neutralizing antibodies. Discovery of this RABV entry inhibitor establishes a new molecular probe to advance further mechanistic and structural characterization of RABV G that may aid in the design of a next-generation clinical candidate against RABV.
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Cangelosi RA, Schwartz EJ, Wollkind DJ. A Quasi-Steady-State Approximation to the Basic Target-Cell-Limited Viral Dynamics Model with a Non-Cytopathic Effect. Front Microbiol 2018; 9:54. [PMID: 29445361 PMCID: PMC5797985 DOI: 10.3389/fmicb.2018.00054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 01/10/2018] [Indexed: 11/27/2022] Open
Abstract
Analysis of previously published target-cell limited viral dynamic models for pathogens such as HIV, hepatitis, and influenza generally rely on standard techniques from dynamical systems theory or numerical simulation. We use a quasi-steady-state approximation to derive an analytic solution for the model with a non-cytopathic effect, that is, when the death rates of uninfected and infected cells are equal. The analytic solution provides time evolution values of all three compartments of uninfected cells, infected cells, and virus. Results are compared with numerical simulation using clinical data for equine infectious anemia virus, a retrovirus closely related to HIV, and the utility of the analytic solution is discussed.
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Affiliation(s)
| | - Elissa J Schwartz
- Department of Mathematics and Statistics, Washington State University, Pullman, WA, United States.,School of Biological Sciences, Washington State University, Pullman, WA, United States
| | - David J Wollkind
- Department of Mathematics and Statistics, Washington State University, Pullman, WA, United States
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Anindita PD, Sasaki M, Nobori H, Sato A, Carr M, Ito N, Sugiyama M, Orba Y, Sawa H. Generation of recombinant rabies viruses encoding NanoLuc luciferase for antiviral activity assays. Virus Res 2016; 215:121-8. [DOI: 10.1016/j.virusres.2016.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/27/2016] [Accepted: 02/05/2016] [Indexed: 12/13/2022]
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Wanjalla CN, Goldstein EF, Wirblich C, Schnell MJ. A role for granulocyte-macrophage colony-stimulating factor in the regulation of CD8(+) T cell responses to rabies virus. Virology 2012; 426:120-33. [PMID: 22341782 DOI: 10.1016/j.virol.2012.01.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 12/19/2011] [Accepted: 01/23/2012] [Indexed: 12/25/2022]
Abstract
Inflammatory cytokines have a significant role in altering the innate and adaptive arms of immune responses. Here, we analyzed the effect of GM-CSF on a RABV-vaccine vector co-expressing HIV-1 Gag. To this end, we immunized mice with RABV expressing HIV-1 Gag and GM-CSF and analyzed the primary and recall CD8(+) T cell responses. We observed a statistically significant increase in antigen presenting cells (APCs) in the spleen and draining lymph nodes in response to GM-CSF. Despite the increase in APCs, the primary and memory anti HIV-1 CD8(+) T cell response was significantly lower. This was partly likely due to lower levels of proliferation in the spleen. Animals treated with GM-CSF neutralizing antibodies restored the CD8(+) T cell response. These data define a role of GM-CSF expression, in the regulation of the CD8(+) T cell immune responses against RABV and has implications in the use of GM-CSF as a molecular adjuvant in vaccine development.
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Affiliation(s)
- Celestine N Wanjalla
- Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Yewdell JW. Designing CD8+ T cell vaccines: it's not rocket science (yet). Curr Opin Immunol 2010; 22:402-10. [PMID: 20447814 PMCID: PMC2908899 DOI: 10.1016/j.coi.2010.04.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 04/12/2010] [Indexed: 01/09/2023]
Abstract
CD8+ T cells play important roles in clearing viral infections and eradicating tumors. Designing vaccines that elicit effective CD8+ T cell responses requires a thorough knowledge of the pathways of antigen presentation in vivo. Here, I review recent progress in understanding the activation of naïve CD8+ T cells in vivo, with particular emphasis on cross-priming, the presentation of protein antigens acquired by dendritic cells from their environment. With the rapid advances in this area of research, the dawn of rational vaccine design is at hand.
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Huang Y, Tang Q, Nadin-Davis SA, Zhang S, Hooper CD, Ming P, Du J, Tao X, Hu R, Liang G. Development of a reverse genetics system for a human rabies virus vaccine strain employed in China. Virus Res 2010; 149:28-35. [DOI: 10.1016/j.virusres.2009.12.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 12/20/2009] [Accepted: 12/22/2009] [Indexed: 11/16/2022]
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Mareeva T, Wanjalla C, Schnell MJ, Sykulev Y. A novel composite immunotoxin that suppresses rabies virus production by the infected cells. J Immunol Methods 2010; 353:78-86. [PMID: 19932697 PMCID: PMC2823984 DOI: 10.1016/j.jim.2009.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 11/01/2009] [Accepted: 11/10/2009] [Indexed: 10/20/2022]
Abstract
Using strepavidin as a scaffold, we have assembled a composite immunotoxin that consists of recombinant Pseudomonas exotoxin A subunit (PE38) and recombinant 25-D1.16 Fab fragment which recognizes the SIINFEKL (pOV8) peptide from ovalbumin in association with H-2K(b) MHC class I protein. The composite immunotoxin exercises cytotoxicity against H-2K(b+) cells sensitized with pOV8 peptide but not with irrelevant peptide. Specific binding of the immunotoxin to H-2K(b+) cells infected with recombinant rabies virus (RV) expressing pOV8 epitope (RV-pOV8) resulted in the suppression of the production of virus particles by the infected cells. This strategy allows readily produce different immunotoxins with desired specificity by combining various targeting and toxin molecules. The results provide a proof of concept that composite immunotoxins can be utilized as novel immunotherapeutics to stop virus spread in the acute phase of the infection allowing winning time for the development of protective immune response.
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Affiliation(s)
- Tatiana Mareeva
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA19107
| | - Celestine Wanjalla
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA19107
| | - Matthias J. Schnell
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA19107
- Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA19107
- Jefferson Vaccine Center, Thomas Jefferson University, Philadelphia, PA19107
| | - Yuri Sykulev
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA19107
- Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA19107
- Jefferson Vaccine Center, Thomas Jefferson University, Philadelphia, PA19107
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Oishi K, Noguchi H, Yukawa H, Inoue M, Takagi S, Iwata H, Hasegawa M, Hayashi S. Recombinant Sendai Virus-Mediated Gene Transfer to Mouse Pancreatic Stem Cells. Cell Transplant 2009; 18:573-80. [PMID: 19775519 DOI: 10.1177/096368970901805-613] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Efficient gene transfer into stem cells is essential for the basic research and for therapeutic applications in gene-modified regenerative medicine. Adenovirus (AdV) vectors, one of the most commonly used types of vectors, can mediate high, albeit transient, levels of expression of the transgene in pancreatic stem/progenitor cells. However, high multiplicity of infection (MOI) with AdV vectors can result in cellular toxicity. Therefore, AdV vectors have been of limited usefulness in clinical applications. In this study, we investigated the in vitro gene transfer efficiency of Sendai virus (SeV) vectors, a paramyxovirus vector that can efficiently introduce foreign genes without toxicity into several cell types, including pancreatic stem cells. The dose-dependent GFP expression of pancreatic stem cells transfected with SeV vectors after 48 h of culture at 37°C was observed. The transfection of pancreatic stem cells with SeV vectors and AdV vectors results in equal expression of the transgene (GFP expression) in the cells after 48 h of culture at 37°C. Although the transfection of pancreatic stem cells with AdV vectors at high MOIs was cytotoxic, transfection with SeV vectors at high MOIs was rarely cytotoxic. In addition, pancreatic stem cells transfected with SeV maintained their differentiation ability. These data suggest that SeV could provide advantages with respect to safety issues in gene-modified regenerative medicine.
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Affiliation(s)
- Koichi Oishi
- Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Hirofumi Noguchi
- Baylor Institute for Immunology Research/Baylor All Saints Medical Center, Baylor Research Institute, Dallas, TX 75204, USA
| | - Hiroshi Yukawa
- Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | | | - Soichi Takagi
- Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Hisashi Iwata
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Aichi 487-8501, Japan
| | | | - Shuji Hayashi
- Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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Plesa G, Snook AE, Waldman SA, Eisenlohr LC. Derivation and fluidity of acutely induced dysfunctional CD8+ T cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:5300-8. [PMID: 18390711 DOI: 10.4049/jimmunol.180.8.5300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dysfunctional CD8(+) T (T(CD8(+))) cells lacking cytokine production have been identified in many viral infections, but their genesis is not well understood. Established results indicate that such cells could be either high avidity that enter a refractory state due to overstimulation or low avidity that are only partially stimulated. Using an acute, resolving infection model that results in rapid production of dysfunctional cells, we show that this IL2 unresponsive phenotype emerges from the low end of the avidity spectrum and is characterized by broad TCR usage and a reduced proliferation rate. Furthermore, the dysfunctional population is extremely fluid, being sustained by high Ag dose but virtually eliminated following low dose boosting. Together, these results suggest that persistence of dysfunctional cells generated in this manner depends upon continual exposure to high Ag levels and that such cells may ultimately predominate if functional cells become exhausted.
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Affiliation(s)
- Gabriela Plesa
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Snook AE, Stafford BJ, Li P, Tan G, Huang L, Birbe R, Schulz S, Schnell MJ, Thakur M, Rothstein JL, Eisenlohr LC, Waldman SA. Guanylyl cyclase C-induced immunotherapeutic responses opposing tumor metastases without autoimmunity. J Natl Cancer Inst 2008; 100:950-61. [PMID: 18577748 DOI: 10.1093/jnci/djn178] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND One of the greatest impediments to cancer immunotherapy is the paucity of antigens that are tumor specific, sufficiently immunogenic, and shared among patients. Mucosa-restricted antigens that are expressed by tumor cells represent a novel class of vaccine targets that are characterized by immunologic privilege, which limits systemic tolerance to those antigens, and immunologic partitioning, which shields mucosae from systemic autoimmune responses. Here we defined the immunogenicity and antitumor efficacy of guanylyl cyclase C (GCC), a protein that is normally restricted to intestinal mucosa and universally expressed by metastatic colorectal cancer. METHODS BALB/c mice (n = 197) were immunized with recombinant GCC-expressing viral vectors before (prophylactic) or after (therapeutic) a lethal challenge of GCC-expressing mouse colon cancer cells, and antitumor efficacy was monitored by quantifying metastasis and survival. Induction of autoimmunity was monitored by histopathology. Induction of GCC-specific B-cell and CD4(+) and CD8(+) T-cell responses were determined by enzyme-linked immunosorbent assay and ELISpot, respectively. Tolerance to GCC was quantified by comparing responses in GCC-deficient (n = 45) and wild-type (n = 69) C57BL/6 mice. Statistical tests were two-sided. RESULTS Immunization with GCC-expressing viral vectors reduced the formation of metastases to liver (control vs GCC: mean = 30.4 vs 3.55 nodules, difference = 26.9 nodules, 95% confidence interval [CI] = 8.47 to 45.3 nodules; P = .008) and lung (control vs GCC: mean = 263 vs 55.7 nodules, difference = 207, 95% CI = 163 to 251; P < .001) and extended the median survival of mice with established lung metastases following therapeutic immunization (control vs GCC: 29 vs 38 days, P = .024), without autoimmunity. Antitumor efficacy reflected asymmetrical tolerance that was characterized by CD8(+) T-cell, but not CD4(+) T-cell or antibody, responses. CONCLUSIONS Immunologic partitioning together with immunologic privilege highlight the potential of mucosa-restricted antigens, particularly GCC, as therapeutic targets for metastatic cancer.
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Affiliation(s)
- Adam E Snook
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 132 South Tenth St, Philadelphia, PA 19107, USA
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