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. 2017 Aug 2;216(7):887–898. doi: 10.1093/infdis/jix370

Figure 2.

Figure 2.

Decline in levels of functional antibodies to merozoites and antibodies to infected erythrocyte (IE) surface antigens over the study period. In a subset of 70 samples, antibody function was measured at 3 time-points (October 2003, May 2004, and October 2004). The predicted mean antibody levels (and 95% confidence intervals [CIs] shown in gray) over time are shown. Day 0 represents October 2003 with days of follow-up indicated on the x-axis. Mean functional antibody half-lives were calculated from the fixed-effects slope component of a mixed-effects model and are represented in years. Antibody half-life for each antibody measure is as follows: A, Opsonic phagocytosis of merozoites, 0.15 (95% reference range, .09–0.40). B, Complement (C1q) fixation on merozoites (95% reference range, 0.70–∞). C, Antibodies to surface antigens of 3D7 IEs, 10.5 (95% reference range, 3.2–∞). D, Antibodies to surface antigens A4var19 IEs 4.0 (95% reference range, 1.4–∞). Abbreviations: pRBC, parasitised red blood cells; VSA, variant surface antigens.