Severe acute respiratory syndrome (SARS) is a life-threatening disease caused by a novel coronavirus termed SARS-CoV. Due to the severity of this disease, the World Health Organization (WHO) recommends that manipulation of active viral cultures of SARS-CoV be performed in containment laboratories at biosafety level 3 (BSL3). The virus was inactivated by ultraviolet light (UV) at 254 nm, heat treatment of 65 degrees C or greater, alkaline (pH > 12) or acidic (pH < 3) conditions, formalin and glutaraldehyde treatments. We describe the kinetics of these efficient viral inactivation methods, which will allow research with SARS-CoV containing materials, that are rendered non-infectious, to be conducted at reduced safety levels.

Heat, UVC irradiation, and S/D treatments effectively inactivate SARS-CoV, whereas octanoic acid treatment is insufficient for inactivation of the virus.

While many clinical hepatitis C virus (HCV) infections are resistant to alpha interferon (IFN-␣Hepatitis C virus (HCV) infects approximately 170 million individuals worldwide and nearly 3 million in the United States alone. Most cases of HCV infection become persistent and may result in chronic liver disease, cirrhosis, and hepatocellular carcinoma. The current combination antiviral therapy of pegylated alpha interferon (IFN-␣) with ribavirin is effective in approximately 50% of individuals treated, while monotherapy with IFN-␣ alone is successful in less than 20% of patients (13). IFN-␣ allows cells to become innately primed for defense against eventual virus attack by inducing the transcription of many genes, some of which are activated during virus infection. Only a few genes have been identified and characterized as mediators of the IFN-␣-induced antiviral response, including the Mx proteins, major histocompatibility complex proteins, 2Ј,5Ј oligoadenylate synthetase, and the double-stranded RNA (dsRNA)-activated protein kinase (PKR) (21). PKR is activated during viral infection, which results in the phosphorylation of the ␣ subunit of eukaryotic translation initiation factor 2 (eIF-2␣) and subsequent translational shutoff. An adenosine deaminase that acts on dsRNA (ADAR1) is also IFN-␣ induced and catalyzes the deamination of adenosine residues in dsRNA (for a review, see reference 17), resulting in inosine substitution. Inosine residues are not abundantly found in cellular mRNAs, but when inosine residues are present, they are transcribed and translated as guanosine residues, which may lead to mutations (1, 24). An RNase that specifically degrades inosine-containing RNA has been described and was proposed to be part of a putative antiviral pathway (18,19). Although antiviral activity has not been attributed to ADAR1, hepatitis delta virus utilizes ADAR1 editing to promote its viral life cycle (15).Typically, dsRNA is found only in cells that are virus infected, and both DNA and RNA viruses may present dsRNA in the cell in the form of replicative intermediates (12). ADAR1 contains three copies of a conserved dsRNA-binding motif also found in PKR (25). Most viruses have developed strategies to evade the effects of IFN-␣. For instance, a singlestranded virus-encoded RNA with partially dsRNA features, adenovirus-associated (VA) RNA I , enhances translation and counteracts the effects of IFN-␣ in adenovirus-infected cells by inhibiting PKR (14). VA RNA has also been shown to bind and inhibit ADAR1 (10). This is the first report implicating RNA editing by ADAR1 in the control of viral replication and may provide a potent strategy for an effective treatment against HCV based on ADAR1 activation. MATERIALS AND METHODSExpression vectors and HCV replicon. The BB7 replicon was a gift of C. M. Rice and K. Blight and was previously described (2). Briefly, the replicon expresses HCV NS3 through NS5B nonstructural genes under the encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES) and neomycin resistance...