FIG. 7.

Evaluation by enzyme immunoassay of the efficacies of different drugs in reducing PrPres accumulation in the spleens of scrapie-infected mice. Mice infected intraperitoneally with the 6PB1 strain were treated intraperitoneally each day for 3 weeks with quinacrine alone (10 mg/kg), chlorpromazine alone (5 mg/kg), both drugs, and MS-8209 (25 mg/kg) or MS1191 (10 mg/kg). The PrPres concentrations in the spleens of the animals after 30 days were evaluated by optical densitometry. Day 30 is the time when the scrapie PrP concentration reaches a plateau in this organ (3). The horizontal line at an absorbance of 0.08 corresponds to the cutoff, calculated as 2.5 times the mean absorbance of the negative controls.