Viral titrations in TZM-bl cells.

<p>Titrations of IMC.LucR only, CM235.LucR and ETH2220.LucR (A), of CM235.2 Env-based viruses (B) and of ETH2220.11B Env-based viruses (C). All titrations were performed in duplicate, in a 4-fold dilution format. Firefly luciferase acitivity (RLU FF, bold lines) was measured 48 hours later. For IMC.LucR only (A), Renilla luciferase activity (RLU LucR, dashed lines) was also measured simultaneously in the same wells. The different viral forms expressing Env of CM235.2 (B) and ETH2220.11B (C) were compared: virus stocks of pseudovirus (diamond), biological isolate (inverted triangle), parental IMC (triangle) and IMC.LucR (circle). Horizontal solid and dashed lines indicate the cut-off values for FF and LucR, respectively.