Inoculum was performed mixing separated normal schizont-stage parasitized (strain FCR-3) E (SPE), with normal or deficient E suspended in growth medium. Parasitemia of inoculum was adjusted to 4% normal SPE, final hematocrit of inoculum was 0.5%. Parasite invasion: ratio between ring-stage parasitemia measured 14 to 18 hours after inoculum and inoculum parasitemia (first cycle invasion), or ratio between ring-stage parasitemia measured 62 to 66 hours after inoculum and schizont-stage parasitemia measured 40 to 44 hours after inoculum (second cycle invasion). Parasite maturation: ratio between trophozoite-stage parasitemia measured 34 to 38 hours after inoculum and ring-stage parasitemia measured 14 to 18 hours after inoculum (first cycle maturation), or ratio between trophozoite-stage parasitemia measured 82 to 86 hours after inoculum and ring-stage parasitemia measured 62 to 66 hours after inoculum (second cycle maturation). Nonparasitized and parasitized E were counted electronically. To assess total parasitemia and relative contribution of RPE, TPE, and SPE, slides were prepared from cultures at indicated times, stained with Diff-Quik parasite stain, and 400 to 1,000 cells examined microscopically. Significance of differences between normal and deficient parasitized E was assessed by t-test for paired samples. For details on P falciparum cultivation and stage separation of parasitized E, see Materials and Methods.