Figure 3: Inhibition of PRRSV type 2 (PA8) and type 1 (LV) replication by lysomotropic agents and ion channel blockers. Z-mac cells seeded in 96-well plates were treated with the various compounds at indicated concentrations for 24 h followed by infection with 100 TCID50 of either PRRSV PA8 (A and B) or LV (C and D). At 18 h pi, culture supernatants were collected for determination of infectious virus yields (TCID50/ml). In parallel, viral RNA was extracted from cells in the same well and subjected to real-time RT-PCR for the N gene of PRRSV PA8 (B) or LV (D). The compounds and their concentrations were as follows: tilmicosin 80 µg/ml, verapamil 50 µM, chloroquine 0.4 µM, amantadine 0.4 mM and ammonium chloride 5 mM. Controls consisted of virus-infected untreated (mock) cultures. Virus titers (A and C) and relative fold changes in viral genomic RNA (B and D) are indicated. Data are shown as mean titers with standard errors (A and C) and relative amounts of RNA with standard errors (B and D).