The human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) genomes encode several auxiliary proteins that have increasingly shown their importance in the virus-host relationship. One of these proteins, Vpx, is unique to the HIV-2/SIVsm lineage and is critical for viral replication in macrophages. The functional basis for this requirement, as well as the Vpx mode of action, has remained unexplained, and it is all the more enigmatic that HIV type 1 (HIV-1), which has no Vpx counterpart, can infect macrophages. Here, we underscore DCAF1 as a critical host effector of Vpx in its ability to mediate infection and long-term replication of HIV-2 in human macrophages. Vpx assembles with the CUL4A-DDB1 ubiquitin ligase through DCAF1 recruitment. Precluding Vpx present in the incoming virions from recruiting DCAF1 in target macrophages leads to a postentry block characterized by defective accumulation of HIV-2 reverse transcripts. In addition, Vpx from SIVsm functionally complements Vpx-defective HIV-2 in a DCAF1-binding-dependent manner. Altogether, our data point to a mechanism in which Vpx diverts the Cul4A-DDB1 DCAF1 ligase to inactivate an evolutionarily conserved factor, which restricts macrophage infection by HIV-2 and closely related simian viruses.

33In the race to contain SARS-CoV-2, efficient detection and triage of infected patients must 34 rely on rapid and reliable testing. In this work we performed the first evaluation of the 35 QIAstat-Dx Respiratory SARS-CoV-2 Panel (QIAstat-SARS) for SARS-CoV-2 detection. This 36 assay is the first rapid multiplex PCR (mPCR) assay including SARS-CoV-2 detection, and is 37 fully compatible with a non-PCR trained laboratory or point-of-care (POC) testing. 38 This evaluation was performed using 69 primary clinical samples (66 NPS, 1 BAL and 1 39 tracheal aspirate and 1 bronchial aspirate) comparing the SARS-CoV-2 detection with the 40 currently WHO recommended RT-PCR (WHO-PCR) workflow. Additionally, a comparative 41 limit of detection (LoD) assessment was performed between QIAstat-SARS and the WHO-42 PCR using a quantified clinical sample. Compatibility of sample pre-treatment for viral 43 neutralisation or viscous samples with the QIAstat-SARS system were also tested. 44 The QIAstat-Dx Respiratory SARS-CoV-2 Panel demonstrated a comparable sensitivity to the 45 WHO recommended assay with a limit of detection at 1000 copies/mL. The overall percent 46 agreement between QIAstat-Dx SARS and WHO-PCR on 69 clinical samples was 97% with a 47 sensitivity at 100% (40/40) and specificity at 93% (27/29). No cross reaction was 48 encountered for any other respiratory viruses or bacteria included in the panel. 49 The QIAstat-SARS rapid multiplex-PCR panel provides a highly sensitive, robust and accurate 50 assay for rapid detection of SARS-CoV-2. This assay allows rapid decisions even in non-PCR 51 trained laboratory or point-of-care testing, allowing innovative organisation. 52 on June 9, 2020 by guest http://jcm.asm.org/ Downloaded from 65 direct insertion of the NPS into the cartridge without additional manipulation. This 66 innovative design allows to test samples on demand in any laboratory, even not PCR trained, 67 or as a point-of-care (PoC) test with minimal training. The QIAstat-Dx SARS version of the 68 panel adds the detection of the SARS-CoV-2 in a previously unused amplification chamber, 69 thus without any change for sampling, extraction and PCR conditions for other respiratory 70 viruses' detection (4, 5). As for a few other rapid PCR assays available to date, results are 71 provided in about one hour, compared to labour-intensive three to four hours in-laboratory 72 workflow of most in-house PCR assays. The comprehensiveness and versatility of the kit can 73 potentially provide a useful tool, allowing innovative organisation to test patients suspected 74 of COVID-19 rapidly and with discrimination of other respiratory pathogens. This is of 75 on June 9, 2020 by guest http://jcm.asm.org/ Downloaded from Page 4 importance to accelerate isolation management, patient orientation and treatment 76 decisions. 77 Here, we report the first independent validation of this new commercial PCR assay for SARS-78 CoV-2 detection, using clinical samples both in laboratory and in the emergency department 79 as a point-of-care t...