FIG. 4.

Homologous BVDV superinfecting particles are blocked at the level of viral entry. (A) Naïve (uninfected) and ncp NADLJiv90⁻-infected (infected) cells were superinfected (Infection) or transfected (Transfection) with ncp NADLJiv90⁻luc. At 6 h postsuperinfection or transfection, the cells were lysed and luciferase activity was determined. (B) Schematic diagram of ncp NADLJiv90⁻pac and ncp NADLJiv90⁻ΔS-pac viral RNAs. (C) ncp NADLJiv90⁻pac (FL), ncp NADLJiv90⁻ΔS-pac (ΔS), and naïve (N) cells were superinfected with ncp NADLJiv90⁻luc. At 6 h postinfection, the cells were lysed and luciferase activity was determined. (D) Naive (N), ncp NADLJiv90⁻pac (FL), ncp NADLJiv90⁻ΔC-pac (ΔC), ncp NADLJiv90⁻ΔE^rns-pac (ΔE^rns), ncp NADLJiv90⁻ΔE1-pac (ΔE1), and ncp NADLJiv90⁻ΔE2-pac (ΔE2) selected MDBK cells were infected with ncp NADLJiv90⁻luc. At 6 h postinfection, the cells were lysed and luciferase activity was determined. The dashed lines represent the background level of the assay from naïve MDBK cells.