ACTB and infection: Nine days after infection, the ERK1/ERK2 ratio was 0.5±0.1 (range 0.4 to 0.7, p<0.0001, n = 5 donors) and the ERK1/β-actin ratio was 0.4±0.1-fold (range 0.2 to 0.6, p<0.0001, n = 5) with respect to control cells transduced with a scrambled sequence (no specific target).