Additional file 4. Titers of pCF-7, pCF7-Vif-4 and engineered pCF7-Vif W/*1 and pCF7-Vif W/*2 variants. Plasmid pCF-7, pCF7-Vif-4, pCF7-Vif W/*1, and pCF7-Vif W/*2 and their engineered M/T and M+ variants were transfected into HEK 293T cells and 2 days post-transfection, cell-free supernatants were inoculated on CrFK cells and serially passaged every A 60 and B 84 h p.i. FFV titers were determined in duplicate using FeFAB reporter cells and are shown as bar diagrams for the different passages. Error bars represent the standard deviation
