FIG 2.

Polyamine depletion restricts the replication of diverse families of viruses. Virus titers were determined following a 4-day 500 μM DFMO treatment and rescue with exogenous polyamines, added at the time of infection. (A) Middle East respiratory syndrome coronavirus (MERS-CoV [MCoV]) at 24 hpi in Vero81 cells; (B) poliovirus (PV) at 24 hpi in HeLa cells; (C) Enterovirus A71 (EV-A71) at 24 hpi in HeLa cells; (D) Yellow fever virus (YFV) at 96 hpi in BHK-21; (E) Japanese encephalitis virus (JEV) at 24 hpi in BHK-21 cells; (F) Dengue virus-1 (DENV1) at 48 hpi in BHK-21 cells; (G) Caribbean isolate of chikungunya virus (CHIKV) at 24 hpi in BHK-21 cells; (H) Rift Valley fever virus (RVFV) at 24 hpi in BHK-21 cells; (I) rabies virus (RABV) at 24 hpi in primary cortical neurons. MERS-CoV, CVB3, JEV, WNV, VSV, and RVFV titers were measured by plaque assay; PV and EV-A71 titers were measured by TCID₅₀; DENV1 and YFV titers were determined by fluorescent focus assay; and RABV infection was determined by quantitation of the signal intensity of somatic inclusions. Statistical significance versus the results for the untreated control was determined using one-tailed Student's t test; n = 3 replicates for all viruses except DENV (n = 8), ZIKV (n = 9), MERS (n = 6), and RABV (n = 6). *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001. Bars and error bars represent mean results ± 1 standard deviation.