ABCB4 and infection: CaSki, VK2E6/E7 or HaCAT cells were transfected with siRNA targeting PLSCR1, multidrug resistance protein-3 (MDR-3), which encodes for an ATP-dependent floppase involved in trafficking of PtdS from the inner to outer membrane, FIC-1, or a negative control siRNA 48 h prior to infection or were treated with 5μM R541 or 0.5% DMSO just prior to infection.