Fig. 4.

Inhibition of multi-cycle (low m.o.i.) but not single-cycle (high m.o.i.) infections. (a) MDCK cells were mock infected or infected with influenza A/PR/8 at an m.o.i. of 0.01 and treated with 1 % DMSO or 5 μM JJ3297. After 72 h, the cells were fixed and stained for NP (upper panels) or DAPI (lower panels). Arrows indicate DAPI-stained cells expressing NP. (b) MDCK cells were infected at an m.o.i. of 5 and treated as described in (a). (c) MDCK cells were mock infected or infected with A/PR/8 at an m.o.i. of 5 (NS1 stained) or 10 (NP stained) and treated with 1 % DMSO or 5 μM JJ3297. Allowing for a single cycle of replication, the cells were fixed after 5 h and stained for NS1, NP or DAPI as indicated. Magnification: (a, b) ×20; (c) ×40 (NP) and ×60 (NS1 and mock).