Fig. 9. Effect of Poly-I on the native and tyrosylated Oregon-HDL₃ cell-association (A) and cholesterol ester-HDL₃ uptake (B). J774-A1 cells were cholesterol loaded with AcLDL (50 µg apo B/ml) as described in Materials and Methods. After an 18 hour equilibration period, the cells were incubated for 3 hours at 37°C with 10 µg apoA/ml of native (•) or tyrosylated () Oregon-HDL₃ (A) or [³H]cholesteryl hexadecyl ether-HDL₃ (B), with or without (control) different concentrations of Poly-I. The non-specific binding was determined in the presence of a 50-fold excess of the corresponding unlabeled HDL₃. After extensive cell washing, the specific cell-associated fluorescence and cellular [³H]cholesteryl hexadecyl ether uptake were determined by flow cytometry and by radioactivity measurement, respectively. Results were espressed as a percentage of the values without Poly-I. Each value is the mean±s.e.m. of three independent experiments using different lipoprotein preparations. ^*P<0.005.