FIG 4.

Polyamine depletion blocks RNA virus replication in combination with IFN-β. (A to C) BHK-21 cells were not treated or pretreated with 500 μM DFMO for 4 days and with 1,000 U IFN-β for 4 h, as indicated, prior to infection with CVB3 at an MOI of 0.1 (A), VSV at an MOI of 0.01 (B), and CHIKV at an MOI of 0.1 (C). Titers were determined at 24 hpi. (D to F) Vero-E6 cells were not treated or treated with 10 μM DENSpm for 16 h and 1,000 U IFN-β for 4 h, as indicated, prior to infection with CVB3 (D), VSV (E), and CHIKV (F). Statistical significance was determined using Student's t test (n ≥ 3). *, P < 0.05; **, P < 0.01; ***, P < 0.001. Error bars represent 1 standard error of the mean.