Aim: There is a critical need for effective therapies that are immediately available to control the spread of COVID-19 disease. Material & methods: Gamunex®-C and Flebogamma® DIF (Grifols) intravenous immunoglobulin (IVIG) products were tested using ELISA techniques for antibodies against several antigens of human common betacoronaviruses that may crossreact with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Results: Both IVIGs showed consistent reactivity to components of the tested viruses. Positive crossreactivity was seen in SARS-CoV, middle east respiratory syndrome-CoV and SARS-CoV-2. For SARS-CoV-2, positive reactivity was observed at IVIG concentrations ranging from 100 μg/ml with Gamunex-C to 1 mg/ml with Flebogamma 5% DIF. Conclusion: Gamunex-C and Flebogamma DIF contain antibodies reacting against SARS-CoV-2 antigens. Studies to confirm the utility of IVIG preparations for COVID-19 management may be warranted.

Hepatitis C virus (HCV) is a major etiological agent of chronic liver disease and hepatocellular carcinoma (HCC). We demonstrate herewith that HCV core proteins encoded by sequences isolated from HCC tumor tissues, but not those derived from their non-tumor counterparts in the same liver, co-localise in vitro and in vivo and co-immunoprecipitate with PKR in hepatocytic Huh7 cells. We show that this association in fact augments the autophosphorylation of PKR and the phosphorylation of the translation initiation factor eIF2a, which are two markers of PKR activity. The present study therefore identi®es a novel model of viruscell interactions whereby a viral protein, the HCV core, activates PKR activity. Oncogene (2001) 20, 5836 ± 5845.

IntroductionFetal bovine serum (FBS) is an animal product used as a medium supplement. The animal origin of FBS is a concern if cultured stem cells are to be utilized for human cell therapy. Therefore, a substitute for FBS is desirable. In this study, an industrial, xeno-free, pharmaceutical-grade supplement for cell culture (SCC) under development at Grifols was tested for growth of human mesenchymal stem cells (hMSCs), cell characterization, and differentiation capacity.MethodsSCC is a freeze-dried product obtained through cold-ethanol fractionation of industrial human plasma pools from healthy donors. Bone marrow-derived hMSC cell lines were obtained from two commercial suppliers. Cell growth was evaluated by culturing hMSCs with commercial media or media supplemented with SCC or FBS. Cell viability and cell yield were assessed with an automated cell counter. Cell surface markers were studied by indirect immunofluorescence assay. Cells were cultured then differentiated into adipocytes, chondrocytes, osteoblasts, and neurons, as assessed by specific staining and microscopy observation.ResultsSCC supported the growth of commercial hMSCs. Starting from the same number of seeded cells in two consecutive passages of culture with medium supplemented with SCC, hMSC yield and cell population doubling time were equivalent to the values obtained with the commercial medium and was consistent among lots. The viability of hMSCs was higher than 90%, while maintaining the characteristic phenotype of undifferentiated hMSCs (positive for CD29, CD44, CD90, CD105, CD146, CD166 and Stro-1; negative for CD14 and CD19). Cultured hMSCs maintained the potential for differentiation into adipocytes, chondrocytes, osteoblasts, and neurons.ConclusionsThe tested human plasma-derived SCC sustains the adequate growth of hMSCs, while preserving their differentiation capacity. SCC can be a potential candidate for cell culture supplement in advanced cell therapies.

The impact of hepatitis C virus NS5A protein mutations on interferon alfa (IFN-␣) signaling pathway, cell proliferation, and viability is an important issue that is still under debate. We have therefore combined transient and stable expression in a human hepatocytic cell line (Huh7) of 3 full-length NS5A sequences, isolated from patients with or without response to IFN-␣ therapy. Expression of all 3 NS5A-reduced IFN-␣ global antiviral activity on both vesicular stomatitis virus (VSV) and encephalomyocarditis virus (EMCV) replication. We did not show, however, an effect of these 3 NS5A proteins on double-stranded RNA-dependent kinase (PKR) expression and activity as well as colocalization and coimmunoprecipitation between NS5A and PKR. We also failed to show an effect of the 3 NS5A mutants tested on cell proliferation and viability. Overall Hepatitis C virus (HCV) is a positive-stranded RNA virus classified as hepacivirus in the Flaviridae family, which exhibits marked viral heterogeneity. 1 The polyprotein precursor is co-and post-translationally processed by both cellular and viral proteases to yield mature, structural and nonstructural proteins. 2-4 HCV is a highly prevalent pathogen and at least 300 million individuals are chronically infected worldwide. 5 The establishment of chronic infection is a major feature of HCV infection, because around 70% to 80% of acutely infected subjects will become chronic carriers, with a high subsequent risk of progression to cirrhosis and hepatocarcinoma. 6 Therapy using interferon alfa (IFN-␣) alone, or in combination with ribavirin, has been shown to be effective in chronic hepatitis C infection, but only 8% to 12% and 30% to 40% of treated patients, respectively, depending on HCV type, viral load, and quasispecies complexity, show a sustained virologic response. [7][8][9] In this context, appraisal of the mechanisms of viral resistance to IFN-␣ therapy is crucial.Several studies have suggested a direct interplay between HCV and IFN-␣-induced cellular signaling. 10,11 Expression of HCV polyprotein in osteosarcoma cells inhibits Jak1-STAT signaling. 12 HCV nonstructural protein NS5A of HCV type 1 has been particularly investigated. In Japanese HCV-1b isolates, an inverse correlation was indeed observed between the number of mutations in a region of NS5A, referred to as the interferon-sensitivity determining region (ISDR; position 2209-2248), and the response to IFN-␣ treatment. 13,14 Such a strict correlation between ISDR mutations and treatment efficacy has not, however, been shown in most studies performed in Europe and the United States. [15][16][17][18][19][20][21] Furthermore, NS5A sequence variability in domains located outside the ISDR, and in particular in the C-terminal part of the protein, is probably also implicated in therapeutic efficacy. 22 Expression of fulllength NS5A-1b but not of ISDR-deleted mutant, renders osteosarcoma 11 and murin fibroblastic cell lines 23 partially resistant to the antiviral effect of IFN-␣ against encephalomyocarditis virus (EMCV) an...