PICV infection is inhibited in cells pre-treated with genistein. Vero cells were pre-treated with 100 μM of genistein for 1 h prior to incubation with PICV (moi 1.0). For western blot experiments, genistein remained present throughout the experiment. (A) Genistein-treated and untreated Vero cells were infected with PICV for 72 h and western blot analyses were performed using the following primary antibodies: monoclonal antibody 3B3.1 (recognizes the PICV NP), the polyclonal anti-peptide antibody GPC (59–79) (recognizes the glycoprotein precursor (GPC) and GP1) (both donated by Dr. M. Buchmeier), and the TfR antibody (Zymed Laboratories, Inc, San Francisco, CA). (B) Supernatants from PICV infected, genistein-treated and untreated Vero cells were harvested 72 h p.i. and analyzed by plaque assays on Vero cells. (C) Supernatants from SIN-infected, genistein (100 μM) pre-treated or untreated Vero cells were harvested 24 h post-infection and analyzed by plaque assay analyses on BHK-21 cells. (D) Vero cells were treated with genistein at various timepoints compared to PICV infection (moi 1.0) and supernatants containing virus were harvested at 72 h after genistein treatment for plaque assays. (E) Vero cells were treated with genistein 48 h after infection, washed to remove any drug, and incubated for an additional 48 h. Supernatants containing virus were harvested for plaque assays. An asterisk represents a p<0.05 as determined by a Student’s t-test when comparing PICV-infected cells to genistein-treated, PICV-infected cells.