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Parker S, D'Angelo J, Buller RM, Smee DF, Lantto J, Nielsen H, Jensen A, Prichard M, George SL. A human recombinant analogue to plasma-derived vaccinia immunoglobulin prophylactically and therapeutically protects against lethal orthopoxvirus challenge. Antiviral Res 2021; 195:105179. [PMID: 34530009 PMCID: PMC9628779 DOI: 10.1016/j.antiviral.2021.105179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 11/22/2022]
Abstract
Orthopoxviruses such as variola and monkeypox viruses continue to threaten the human population. Monkeypox virus is endemic in central and western Africa and outbreaks have reached as far as the U.S. Although variola virus, the etiologic agent of smallpox, has been eradicated by a successful vaccination program, official and likely clandestine stocks of the virus exist. Moreover, studies with ectromelia virus (the etiological agent of mousepox) have revealed that IL-4 recombinant viruses are significantly more virulent than wild-type viruses even in mice treated with vaccines and/or antivirals. For these reasons, it is critical that antiviral modalities are developed to treat these viruses should outbreaks, or deliberate dissemination, occur. Currently, 2 antivirals (brincidofovir and tecovirimat) are in the U.S. stockpile allowing for emergency use of the drugs to treat smallpox. Both antivirals have advantages and disadvantages in a clinical and emergency setting. Here we report on the efficacy of a recombinant immunoglobulin (rVIG) that demonstrated efficacy against several orthopoxviruses in vitro and in vivo in both a prophylactic and therapeutic fashion. A single intraperitoneal injection of rVIG significantly protected mice when given up to 14 days before or as late as 6 days post challenge. Moreover, rVIG reduced morbidity, as measured by weight-change, as well as several previously established biomarkers of disease. In rVIG treated mice, we found that vDNA levels in blood were significantly reduced, as was ALT (a marker of liver damage) and infectious virus levels in the liver. No apparent adverse events were observed in rVIG treated mice, suggesting the immunoglobulin is well tolerated. These findings suggest that recombinant immunoglobulins could be candidates for further evaluation and possible licensure under the FDA Animal Rule.
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Affiliation(s)
- Scott Parker
- Division of Infectious Diseases, Department of Internal Medicine, Saint Louis University, and St. Louis VA Medical Center, St. Louis, MO, 63104, USA
| | - June D'Angelo
- Division of Infectious Diseases, Department of Internal Medicine, Saint Louis University, and St. Louis VA Medical Center, St. Louis, MO, 63104, USA
| | - R Mark Buller
- Department of Molecular Microbiology and Immunology, Saint Louis University, St. Louis, MO, 63104, USA
| | - Donald F Smee
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, 84322, USA
| | - Johan Lantto
- Symphogen, Pederstrupvej 93, DK-2750, Ballerup, Denmark
| | | | - Allan Jensen
- Symphogen, Pederstrupvej 93, DK-2750, Ballerup, Denmark
| | - Mark Prichard
- Department of Pediatrics, University of Alabama, Birmingham, AL, 35233, USA
| | - Sarah L George
- Division of Infectious Diseases, Department of Internal Medicine, Saint Louis University, and St. Louis VA Medical Center, St. Louis, MO, 63104, USA.
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Crump R, Korom M, Buller RM, Parker S. Buccal viral DNA as a trigger for brincidofovir therapy in the mousepox model of smallpox. Antiviral Res 2016; 139:112-116. [PMID: 28039021 DOI: 10.1016/j.antiviral.2016.12.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 12/16/2016] [Accepted: 12/22/2016] [Indexed: 11/15/2022]
Abstract
Orthopoxviruses continue to pose a significant threat to the population as potential agents of bioterrorism. An intentional release of natural or engineered variola virus (VARV) or monkeypox viruses would cause mortality and morbidity in the target population. To address this, antivirals have been developed and evaluated in animal models of smallpox and monkeypox. One such antiviral, brincidofovir (BCV, previously CMX001), has demonstrated high levels of efficacy against orthopoxviruses in animal models and is currently under clinical evaluation for prevention and treatment of diseases caused by cytomegaloviruses and adenoviruses. In this study we use the mousepox model of smallpox to evaluate the relationship between the magnitude of the infectious virus dose and an efficacious BCV therapy outcome when treatment is initiated concomitant with detection of ectromelia virus viral DNA (vDNA) in mouse buccal swabs. We found that vDNA could be detected in buccal swabs of some, but not all infected mice over a range of challenge doses by day 3 or 4 postexposure, when initiation of BCV treatment was efficacious, suggesting that detection of vDNA in buccal swabs could be used as a trigger to initiate BCV treatment of an entire potentially exposed population. However, buccal swabs of some mice did not become positive until 5 days postexposure, when initiation of BCV therapy failed to protect mice that received high doses of virus. And finally, the data suggest that the therapeutic window for efficacious BCV treatment decreases as the virus infectious dose increases. Extrapolating these findings to VARV, the data suggest that treatment should be initiated as soon as possible after exposure and not rely on a diagnostic tool such as the measurement of vDNA in buccal cavity swabs; however, consideration should be given to the fact that the behavior/disease-course of VARV in humans is different from that of ectromelia virus in the mouse.
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Affiliation(s)
- Ryan Crump
- Saint Louis University School of Medicine, 1100 S. Grand Blvd, St. Louis, MO 63104, USA
| | - Maria Korom
- The George Washington University, School of Medicine and Health Sciences, Department of Microbiology, Immunology and Tropical Medicine, 2300 Eye Street, NW Washington, DC 20037, USA
| | - R Mark Buller
- Saint Louis University School of Medicine, 1100 S. Grand Blvd, St. Louis, MO 63104, USA
| | - Scott Parker
- Saint Louis University School of Medicine, 1100 S. Grand Blvd, St. Louis, MO 63104, USA.
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