This devastating epidemic in nonendemic areas highlights an urgent need for the development of therapeutics against emerging and reemerging filoviruses. Monoclonal antibodies (mAbs) show great promise for development of effective filovirus antibody treatments [3]. Democratic Republic of Congo [1]. Cumulatively, these outbreaks resulted in a case-fatality rate of 33.7%, which is comparable to that of Ebola disease (EBOV) infections, including the Western African epidemic of 2013C2016 (41.4%) [2]. This devastating epidemic in nonendemic areas shows an urgent need for the development of therapeutics against growing and reemerging filoviruses. Monoclonal antibodies (mAbs) show great promise for development of effective filovirus LY2109761 antibody treatments [3]. Mouse models have been widely used to display filovirus mAbs [4C8]. However, wild-type filoviruses do not cause any apparent illness in adult, immunocompetent laboratory mice no matter dose or route of inoculation [9C11]. To cause a lethal disease, filoviruses must 1st become adapted to mice. Among ebolaviruses, a mouse-adapted variant has been described only for EBOV [11]. The adaptation of filoviruses to mice, at least in part, is associated with modified interactions with the interferon (IFN) system, which plays a critical part in the resistance of mice to ebolavirus infections [12]. During adaptation, viruses conquer this barrier by accumulating mutations, permitting subversion of the murine immune system. Strains of mice with disrupted IFN response consequently represent an alternative model of filovirus infections that does not require adaptation of disease. Knockout (KO) mice lacking the receptor for IFN-/ (IFNAR) [13] or the cytoplasmic transmission transducer and activator of transcription 1 (STAT1) protein are susceptible to illness by wild-type filoviruses [14]. STAT1 signals the binding of IFN-/ and IFN- LY2109761 to cell-surface receptors and is essential for IFN-mediated transcription of genes triggering antiviral state of the cells [15]. However, inoculation of IFNAR KO mice with wild-type BDBV still does not cause medical indications of disease, excess weight loss, or lethality [13]. STAT1-deficient mice are susceptible to wild-type EBOV, Sudan ebolavirus, Reston ebolavirus (RESTV), Marburg disease, and Ravn disease [14]. Inside a earlier study, we used an EBOV reverse genetics system to generate chimeric filoviruses in which the only envelope glycoprotein (GP) was replaced with the counterparts of heterologous filoviruses, with each producing disease expressing enhanced green fluorescent protein (eGFP) [16]. We shown that these Rabbit Polyclonal to PDGFRb viruses can be used as tools for screening panels of mAbs specific for multiple filoviruses [5]. In this study, we tested feasibility of using one of these viruses for screening mAb treatment in mice. METHODS Viruses The building of eGFP-expressing EBOV/BDBV-GP disease was published previously [16]. To generate its derivative not expressing eGFP, the full-length clone was digested with BsiWI restriction endonuclease to remove the eGFP gene, and then re-ligated. The producing plasmid was used to save the chimeric EBOV enveloped with BDBV-GP as previously explained [17]. The complete nucleotide sequences of the chimeric disease and the related full-length clone, pEBO_BDBV-GP plasmid, have been deposited in GenBank (accession figures MH464888 and MH464889, respectively). Wild-type BDBV, strain 200706291 Uganda, which was originally LY2109761 isolated from your serum of a patient during the 1st known outbreak [18], was passaged 3 times in Vero-E6 cells. Wild-type EBOV, strain Mayinga (GenBank accession quantity AY142960), was from the US Army Medical Study Institute of Infectious Diseases through Dr Heinz Feldmann (while at the Canadian National Microbiology Laboratory, Winnipeg) and Dr Michael R. Holbrook (while at the University or college of Texas Medical Branch [UTMB]), and passaged 4 instances in Vero-E6 cells. Mice Illness With BDBV and EBOV/BDBV-GP Viruses The animal protocols for experiments with mice were authorized by the UTMB Institutional Animal Care and Use Committee (IACUC). The experiments were performed in the Animal Biosafety Level 4 (ABSL-4) facility of the Galveston National Laboratory. Six- to 7 week-old STAT1 KO mice (129S6/SvEv-test was utilized for analysis of viremia data. RESULTS To test if STAT1 KO mice can be used like a model for BDBV illness, we inoculated animals with 1000 PFU of the disease from the intraperitoneal route. However, animals demonstrated only a slight and transient body weight decrease that reached the maximum (approximately 10% excess weight loss) on days 5C6, which was completely restored by days 7C8, with subsequent small fluctuations (Number 1B, left panels). This reduction of excess weight corresponded temporally to the increase in disease score, which did not surpass 4 (slight illness). All animals survived the challenge, suggesting that.
This devastating epidemic in nonendemic areas highlights an urgent need for the development of therapeutics against emerging and reemerging filoviruses
