(A) Drug responses of 3D7 wild-type (WT) and Pfmspdbl2 knockout (KO) lines to halofantrine (HFN), mefloquine (MFQ), and lumefantrine (LUM), measured by tritium-labeled hypoxanthine incorporation. (B) Drug responses of 3D7 WT and KO lines to chloroquine (CQ), artemisinin (ART), and atovaquone (ATV). The values shown are means ± standard deviations of at least two separate assays run on different days. *, P < 0.05 (two-tailed, unpaired t test).