FIG. 4.

The induction of Stat-1 protein by IFN-α is impaired in HPV31 cells. (A) Western blot analysis of equal amounts of protein lysates from NHKs and LKP31 cells treated with IFN-α (100 or 500 U/ml) to detect Stat-1 protein level. Stat-1 protein migrates in SDS-PAGE as a doublet with molecular weights of 91,000 and 84,000. Quantitative estimation of the results in panel A was done with a densitometer and shown graphically in panel B. The induction of Stat-1 protein by IFN-α reaches comparable levels in LKP31 cells and NHKs with a higher dose (1,000 U/ml) and longer time. (C) Western blot analysis of equal amount of protein lysates from NHKs or LKP31 cells treated with IFN-α to detect Stat-1 protein. Quantitative estimation of the results in panel C was done with a densitometer and shown graphically in panel D.