FIG 5.

Polyamine depletion limits viral replication in a time-dependent manner. BHK-21 cells were treated with 10 μM DENSpm at the indicated times prior to and after 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) for 24 h. (D) Cell counts (open circles, left axis) and viability (closed circles, right axis) were measured on uninfected Vero-E6 cells treated with DENSpm for different times as described in the legend to panels A to C. Dashed lines indicate levels corresponding to the results for untreated cells. (E to I) Confluent monolayers of cells were treated with DFMO and a polyamine mixture (PA) at the time of infection with CVB3 (E), VSV (F), CHIKV (G), ZIKV (H), and SINV (I) in a plaque-reduction assay. Plaques were developed after 4 days (H), 3 days (E, G, and I), or 2 days (F). (J) Representative plaques from CVB3, CHIKV, and ZIKV, treated as indicated. 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.