Characterization of a model of lethal dengue virus 2 infection in C57BL/6 mice deficient in the alpha/beta interferon receptor

Abstract

Dengue virus (DENV) causes dengue fever and dengue haemorrhagic fever/dengue shock syndrome, both considered major public-health problems worldwide. We generated a lethal DENV-2 strain (D220) by 10 additional cycles of subcutaneous inoculation of mice with supernatant from mosquito cells infected with the previously characterized strain D2S10, followed by harvesting of serum. D220 induces mortality at ten-fold lower doses than D2S10 in mice lacking only the alpha/beta interferon (IFN-a/b) receptor in C57BL/6 or 129 backgrounds under both non-enhanced and antibody-enhanced conditions. Sequence analysis of the complete viral genome revealed five amino acid changes between D220 and D2S10, of which two (K122I in envelope and V115A in NS4B) appear to account for the observed phenotypic differences between the viruses. By causing mortality at lower doses in C57BL/6 mice lacking only the IFNa/b receptor, D220 constitutes an improved tool for study of DENV-induced pathogenesis, as well as for testing potential vaccines and antiviral drugs against DENV.The four serotypes of dengue virus (DENV-1-4) are mosquitoborne and cause dengue fever (DF) and dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS). Found in tropical and subtropical regions of the world, DENV causes an estimated 50-100 million infections annually and places over 3 billion people at risk of infection (WHO, 2009). Most primary DENV infections with any serotype are asymptomatic or lead to the self-limited febrile illness DF; however, secondary infection with a different DENV serotype leads to increased risk of developing severe dengue disease (Halstead, 2007). This increase in severity upon secondary infection is thought to be mediated in part via antibody-dependent enhancement (ADE), whereby interaction between antibodies generated during a prior infection and the current infecting serotype can lead to increased uptake of virus via Fc receptors expressed on susceptible myeloid cells (Halstead, 2003).Establishing a small-animal model is an important step in understanding the mechanisms underlying dengue pathogenesis and immunity. The first mouse models used high doses of neurovirulent DENV strains delivered intracranially into immunocompetent mice; this caused neurotropic disease and paralysis in infected mice, which is typically not observed in human dengue (Raut et al., 1996;Schlesinger, 1977). One of the second-generation models used a neurotropic mouseadapted DENV2 strain in mice of the 129/Sv mouse background deficient in alpha/beta interferon (IFN-a/b) and IFN-c receptors (AG129 mice) (Johnson & Roehrig, 1999;Zompi & Harris, 2012). In more recent work, a peripherally adapted DENV-2 virus, designated D2S10, was generated by alternately passaging the Taiwanese DENV-2 isolate PL046 between Aedes albopictus C6/36 cells and AG129 mouse serum. The D2S10 virus was lethal in AG129 mice at 10 7 p.f.u. and induced a vascular leak phenotype mediated in part by tumour necrosis factor alpha (TNF-a) (Shresta et al., 2006), which is similar to observations in s...

Type I Interferon Signals in Macrophages and Dendritic Cells Control Dengue Virus Infection: Implications for a New Mouse Model To Test Dengue Vaccines

“…This method caused neurotropic disease and paralysis, neither of which is typically observed in humans. More recently, immunocompromised mice lacking type I and/or type II IFN receptors have been generated (10,11). Dengue infection in these mice recapitulates some aspects of the human disease, such as cytokine storm, vascular leakage, TNF-␣ production, hemorrhage, and nonparalytic death (36).…”

“…However, the complete absence of IFN signaling renders these mice profoundly immunodeficient (reviewed in reference 5), which means data generated in these animals must be interpreted with caution. A recent report proposed an improvement to the AG129 model; mice lacking the IFN-␣/␤ receptor but with intact IFN-␥ signaling were highly susceptible to lethal infection with a mouse-adapted dengue virus strain and thus were proposed by the authors to be more useful for vaccine testing than the AG129 mice (10). However, the potential impact of a global lack of type I IFN receptor (IFNAR) signaling on the immune response to both dengue virus infection and vaccination cannot be overlooked.…”

Characterization of lethal dengue virus type 4 (DENV-4) TVP-376 infection in mice lacking both IFN-α/β and IFN-γ receptors (AG129) and comparison with the DENV-2 AG129 mouse model

“…Recently, DENV-2 strains have been identified that produce a disease that contains features of the human illness, such as thrombocytopenia, viraemia, cytokine storm, and/or vascular leakage (Shresta et al, 2006;Tan et al, 2010;Mota & RicoHesse, 2009). Lethal DENV-2 infection models have been described in immunocompromised mouse strains, particularly in AG129 mice, deficient in IFN-a/b receptor (IFN-a/ bR) and IFN-c receptor (IFN-cR) signalling, and A129 and ifnar 2/2 mice, deficient in IFN-a/bR only (Johnson & Roehrig, 1999;Orozco et al, 2012;Prestwood et al, 2012;Zellweger et al, 2010;Balsitis et al, 2010). Other strains of immunocompromised mice are resistant to lethal infection by DENV-2, such as mice deficient in IFN regulatory factors 3 and 7 (IRF3 and IRF7), signal transducer and activator of transcription factor 1 or 2 (STAT1 or STAT2), and mitochondrial antiviral signalling protein (MAVS) (Chen et al, 2013;Perry et al, 2009Perry et al, , 2011Ashour et al, 2010).…”

“…IFN-cR signalling is sufficient for mouse resistance to TVP-376, but resistance to D2S10 requires both IFN-a/bR and IFN-cR Studies with DENV-2 strains have shown that AG129 mice are more susceptible to infection than A129 mice (Orozco et al, 2012;Prestwood et al, 2012). However, no studies have been conducted with the other DENV serotypes.…”

Spleen Tyrosine Kinase (Syk) Mediates IL-1β Induction by Primary Human Monocytes during Antibody-enhanced Dengue Virus Infection

“…This is particularly informative because DENV does not cause relevant disease in immunocompetent mice unless extremely high inoculums are used (43)(44)(45)(46)(47)(48)(49)(50)(51). Using these valuable antibodies in ADE studies with primary human monocytes allows identification of important signaling pathways that represent potential therapeutic targets for the treatment of severe dengue disease.…”