FIGURE 8.

Response index of PK1 cells to RML and inhibition by swa are a function of PrP^C expression level. PK1 cells were transfected with a serial dilution of PrP siRNA to attenuate PrP^C expression. After 2 days, aliquots of the transfected cells were subjected to Western blot analysis for PrP^C quantitation and to the SSCA using RML brain homogenate in the presence or absence of 2 μg of swa/ml. A, Western blot showing PrP^C expression of PK1 cells treated with siRNA at the levels indicated. Unt, untreated cells. B, quantification of A. PrP^C expression was reduced to ∼3% of untreated controls. C, RI of PK1 cells infected in the presence or absence of swa, as a function of PrP^C expression at the time of infection. D, RI_−swa/RI_+swa decreased with decreasing levels of PrP^C expression. Lipo, Lipofectamine only. The experiment was performed twice; each data point is from four samples.