Cell culture systems for isolation of SARS-CoV-2 clinical isolates and generation of recombinant virus.

A simple and robust cell culture system is essential for generating authentic SARS-CoV-2 stocks for evaluation of viral pathogenicity, screening of antiviral compounds, and preparation of inactivated vaccines. Evidence suggests that Vero E6, a cell line commonly used in the field to grow SARS-CoV-2, does not support efficient propagation of new viral variants and triggers rapid cell culture adaptation of the virus. We generated a panel of 17 human cell lines overexpressing SARS-CoV-2 entry factors and tested their ability to support viral infection. Two cell lines, Caco-2/AT and HuH-6/AT, demonstrated exceptional susceptibility, yielding highly concentrated virus stocks. Notably, these cell lines were more sensitive than Vero E6 cells in recovering SARS-CoV-2 from clinical specimens. Further, Caco-2/AT cells provided a robust platform for producing genetically reliable recombinant SARS-CoV-2 through a reverse genetics system. These cellular models are a valuable tool for the study of SARS-CoV-2 and its continuously emerging variants.

[Prognostic value of stromal immunolabelling by MMP-2, MT1-MMP and TIMP-2 in clinically localized prostate cancer]. / Valeur pronostique de l'immunomarquage du stroma par la MMP-2, la MT1-MMP et le TIMP-2 dans l'adénocarcinome prostatique cliniquement localisé.

INTRODUCTION: Metalloproteinases (MMPs) promote cell migration and tumour invasion by degradation of the extracellular matrix. Activators and inhibitors (such as membrane type 1-matrix metalloproteinase or MT1-MMP and tissue inhibitor metalloproteinase 2 or TIMP-2) regulate metalloproteinase activity. The objective of this study was to determine the prognostic value of stromal immunolabelling with MMP-2, MT1-MMP and TIMP-2 in clinically localized prostate cancer. MATERIAL AND METHODS: The immunohistochemical study was performed on 30 radical prostatectomy specimens. The results were compared to preoperative PSA, Gleason score, pT stage and biochemical recurrence with a minimum follow-up of 5 years. RESULTS: Stromal immunolabelling with MMP-2 is correlated with stage pT3 (p=0.0022, OR=17.5). No correlation was observed with the other histoprognostic parameters. No statistical link was established with MT1-MMP and TIMP-2. CONCLUSION: Stromal immunolabelling with MMP-2 is a histoprognostic marker of capsular effraction in prostatic adenocarcinoma. When performed on prostatic biopsies, it can predict the pT3 stage, allowing adaptation of the initial treatment in some patients.