ERVW-1 and infection: Using a 2G12-capture, biotinylated-VRC01 detection ELISA format, which does not distinguish between native-like trimers and other forms of Env, we estimated that the highest overall level of Env expression measured in the ChAdOx1.BG505s cultures was ~360 ng/ml at 48 h after infection at an MOI of 50, whereas for the MVA.BG505s cultures, the maximum expression at the same 48-h time-point was only ~4.5 ng/ml at an MOI of 5.