Correlation between the phospholipid content of HDL and its ability to elicit efflux. HDL (density between 1.063 and 1.21 g/ml) isolated from BAC⁺ApoE^–/– and control ApoE^–/– mice was used for the quantification of phospholipid content and its ability to elicit cholesterol efflux. Phospholipid was quantified using a previously characterized method (21). Efflux was measured using Fu5AH cells, using protocols previously described (25). Linear regression analysis was performed on the percentage of phospholipid content of the HDL and the percentage of efflux elicited. The phospholipid content of HDL accounts for 68% of its ability to induce cholesterol efflux. PL, phospholipid.