Figure 2. Plasmodium falciparum replication rate varies widely among donor RBCs.

(A, B) Growth of P. falciparum lab strain 3D7 (A) or clinical isolate Th.026.09 (B) over a full 48-hr cycle in donor RBCs (see Figure 1C). Growth is presented relative to the average non-carrier rate after correction for batch effects (Figure 2—figure supplement 1; see Materials and methods), including comparison to a repeated RBC control shown in gray. Each carrier group was compared to unrelated non-carriers using Student’s t-test, except in cases where N=1, where asterisks instead indicate the percentile of the non-carrier distribution. Repeated measurements of 11 donors are shown in Figure 2—figure supplement 2. (C) Per-sample growth rates are correlated between the two P. falciparum strains. (D–F) As in (A–C) but for P. falciparum invasion efficiency (see Figure 1C). R² and p-values are derived from OLS regression. *p<0.1; **p<0.05; ***p<0.01. RBC, red blood cell.

Figure 2—figure supplement 1. Linear models of batch effects on parasite fitness.

PMR: parasite multiplication rate.

Figure 2—figure supplement 2. Repeatability of parasite assays in the same donors over time.

Twelve participants (including the weekly control, 1111) donated blood in multiple weeks for independent experiments. Repeated donors were non-carriers except 6443, who carried the HbAC allele; and 7160, 8597, and 4278, who carried alleles for mild G6PD deficiency. Growth and invasion data are shown after standardization and batch correction, as described in Materials and methods. Pearson’s rho is calculated between the first and second assays and can range from –1 to 1.