FIG. 2.

(A) Plaque formation ability of A12-LLV2 on PK or IBRS2 cells. Cells were infected with approximately 100 PFU of A12-LLV2, overlaid, and stained at 36 h postinoculation. (B) Induction of IFN-α or IFN-β mRNA in PK or IBRS2 cells. Cells were infected with A12-IC, A12-LLV2, or mock infected for 6 h and used in RT-PCR as described in Materials and Methods. Aliquots from RT reactions were used in three separate PCR assays with IFN-α, IFN-β, and β-actin primers. DNA from uninfected PK or IBRS2 cells was used in PCR assays as target controls. IFN-α, IFN-β, and β-actin RT-PCR products are 379, 452, and 890 bp, respectively. Lanes MW, 1-kb-ladder DNA molecular weight markers.