B cell–associated JFH-1 acquires resistance to trypsin and nAbs. CD40L/IL-4–stimulated L3055–Bcl-2 (□) and PBMC-derived primary () B cells bound JFH-1 were incubated for 1, 2, or 3 hours at 37°C and untreated (UT) or treated with trypsin (2.5 μg/mL) (A), control, or HCV⁺ IgG (200 μg/mL) (B) for 5 and 15 minutes, respectively. Enzyme and unbound IgG was removed by extensive washing, the B cells were cocultured with Huh-7.5 cells, and transinfection was quantified. Data represent the SEM FFUs per 10⁶ B cells from 3 replicate infections.