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Graham JB, Swarts JL, Edwards KR, Voss KM, Green R, Jeng S, Miller DR, Mooney MA, McWeeney SK, Ferris MT, Pardo-Manuel de Villena F, Gale M, Lund JM. Correlation of Regulatory T Cell Numbers with Disease Tolerance upon Virus Infection. Immunohorizons 2021; 5:157-169. [PMID: 33893179 PMCID: PMC8281504 DOI: 10.4049/immunohorizons.2100009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 02/19/2021] [Indexed: 11/19/2022] Open
Abstract
The goal of a successful immune response is to clear the pathogen while sparing host tissues from damage associated with pathogen replication and active immunity. Regulatory T cells (Treg) have been implicated in maintaining this balance as they contribute both to the organization of immune responses as well as restriction of inflammation and immune activation to limit immunopathology. To determine if Treg abundance prior to pathogen encounter can be used to predict the success of an antiviral immune response, we used genetically diverse mice from the collaborative cross infected with West Nile virus (WNV). We identified collaborative cross lines with extreme Treg abundance at steady state, either high or low, and used mice with these extreme phenotypes to demonstrate that baseline Treg quantity predicted the magnitude of the CD8 T cell response to WNV infection, although higher numbers of baseline Tregs were associated with reduced CD8 T cell functionality in terms of TNF and granzyme B expression. Finally, we found that abundance of CD44+ Tregs in the spleen at steady state was correlated with an increased early viral load within the spleen without an association with clinical disease. Thus, we propose that Tregs participate in disease tolerance in the context of WNV infection by tuning an appropriately focused and balanced immune response to control the virus while at the same time minimizing immunopathology and clinical disease. We hypothesize that Tregs limit the antiviral CD8 T cell function to curb immunopathology at the expense of early viral control as an overall host survival strategy.
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Affiliation(s)
- Jessica B Graham
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Jessica L Swarts
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Kristina R Edwards
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Kathleen M Voss
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | - Richard Green
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | - Sophia Jeng
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University, Portland, OR.,OHSU Knight Cancer Institute, Oregon Health & Science University, Portland, OR
| | - Darla R Miller
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Michael A Mooney
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University, Portland, OR.,OHSU Knight Cancer Institute, Oregon Health & Science University, Portland, OR
| | - Shannon K McWeeney
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University, Portland, OR.,OHSU Knight Cancer Institute, Oregon Health & Science University, Portland, OR.,Oregon Clinical and Translational Research Institute, Oregon Health & Science University, Portland, OR
| | - Martin T Ferris
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Fernando Pardo-Manuel de Villena
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC; and
| | - Michael Gale
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University, Portland, OR
| | - Jennifer M Lund
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA; .,Department of Global Health, University of Washington, Seattle, WA
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Abstract
Flaviviruses are a genus of (+)ssRNA (positive ssRNA) enveloped viruses that replicate in the cytoplasm of cells of diverse species from arthropods to mammals. Many are important human pathogens such as DENV-1-4 (dengue virus types 1-4), WNV (West Nile virus), YFV (yellow fever virus), JEV (Japanese encephalitis virus) and TBEV (tick-borne encephalitis). Given their RNA genomes it is not surprising that flaviviral life cycles revolve around critical RNA transactions. It is these we highlight in the present article. First, we summarize the mechanisms governing flaviviral replication and the central role of conserved RNA elements and viral protein-RNA interactions in RNA synthesis, translation and packaging. Secondly, we focus on how host RNA-binding proteins both benefit and inhibit flaviviral replication at different stages of their life cycle in mammalian hosts. Thirdly, we cover recent studies on viral non-coding RNAs produced in flavivirus-infected cells and how these RNAs affect various aspects of cellular RNA metabolism. Together, the article puts into perspective the central role of flaviviral RNAs in modulating both viral and cellular functions.
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Genetic analysis of West Nile virus isolates from an outbreak in Idaho, United States, 2006-2007. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:4486-506. [PMID: 24065039 PMCID: PMC3799518 DOI: 10.3390/ijerph10094486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/12/2013] [Accepted: 09/16/2013] [Indexed: 12/26/2022]
Abstract
West Nile virus (WNV) appeared in the U.S. in 1999 and has since become endemic, with yearly summer epidemics causing tens of thousands of cases of serious disease over the past 14 years. Analysis of WNV strains isolated during the 2006–2007 epidemic seasons demonstrates that a new genetic variant had emerged coincidentally with an intense outbreak in Idaho during 2006. The isolates belonging to the new variant carry a 13 nt deletion, termed ID-Δ13, located at the variable region of the 3′UTR, and are genetically related. The analysis of deletions and insertions in the 3′UTR of two major lineages of WNV revealed the presence of conserved repeats and two indel motifs in the variable region of the 3′UTR. One human and two bird isolates from the Idaho 2006–2007 outbreaks were sequenced using Illumina technology and within-host variability was analyzed. Continued monitoring of new genetic variants is important for public health as WNV continues to evolve.
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Hughes AL, Irausquin S, Friedman R. The evolutionary biology of poxviruses. INFECTION GENETICS AND EVOLUTION 2009; 10:50-9. [PMID: 19833230 DOI: 10.1016/j.meegid.2009.10.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 10/01/2009] [Accepted: 10/02/2009] [Indexed: 11/29/2022]
Abstract
The poxviruses (family Poxviridae) are a family of double-stranded viruses including several species that infect humans and their domestic animals, most notably Variola virus (VARV), the causative agent of smallpox. The evolutionary biology of these viruses poses numerous questions, for which we have only partial answers at present. Here we review evidence regarding the origin of poxviruses, the frequency of host transfer in poxvirus history, horizontal transfer of host genes to poxviruses, and the population processes accounting for patterns of nucleotide sequence polymorphism.
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Affiliation(s)
- Austin L Hughes
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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Grinev A, Daniel S, Stramer S, Rossmann S, Caglioti S, Rios M. Genetic variability of West Nile virus in US blood donors, 2002-2005. Emerg Infect Dis 2008; 14:436-44. [PMID: 18325259 PMCID: PMC2570840 DOI: 10.3201/eid1403.070463] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
This virus is diverging from precursor isolates as its geographic distribution expands. West Nile virus (WNV) was detected in the United States in 1999, has reoccurred every summer since, and has become endemic. Transfusion transmission was documented in 2002, and screening of blood donations for WNV began in 2003. We investigated genetic variation of WNV in human isolates obtained from specimens collected from 30 infected blood donors who tested positive for WNV RNA during 2002–2005. Complete genomic sequences of 8 isolates and structural gene sequences from 22 additional isolates were analyzed. We found some genetic diversity in isolates from different geographic regions and genetic divergence from reported sequences from epidemics in 1999–2001. Nucleotide divergence of structural genes showed a small increase from 2002 (0.18%) to 2005 (0.37%), suggesting absence of strong selective pressure and limited genetic evolution of WNV during that period. Nevertheless, WNV has continued to diverge from precursor isolates as geographic distribution of the virus has expanded.
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Affiliation(s)
- Xiaonan Yang
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai and National Engineering Center for BioChip at Shanghai, Shanghai 201203, China;
- Laboratory of Microbial Molecular Physiology, Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hongliang Yang
- Laboratory of Microbial Molecular Physiology, Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- Department of Microbiology and Parasitology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Gangqiao Zhou
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 102206, China
| | - Guo-Ping Zhao
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai and National Engineering Center for BioChip at Shanghai, Shanghai 201203, China;
- Laboratory of Microbial Molecular Physiology, Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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