FIG. 3.

Pretreatment of CCD-1122Sk cells with IFN antibody-treated supernatant has little effect on NDV growth. NDV-infected culture supernatants from either normal cells (CCD-1122Sk) (A) or tumor cells (HT-1080) (B) were treated with neutralizing antibodies against IFN-α and IFN-β before pretreatment of fresh CCD-1122Sk cells. The cells were then infected with NDV at an MOI of 0.001. Viral titers were determined in the culture medium at various times postinfection. The viral titers of control infections (filled squares) differed markedly from those of cultures that were pretreated with just the supernatant (triangles) but not from those of cultures that were pretreated with antibody-treated supernatant (open squares).