(A) CD107a⁺ monocytes after stimulation with uninfected (uRBC) or infected red blood cells (iRBC). PBMCs from primary infected (n = 5) and previously exposed individuals (n = 6) from acute and matched 12-month (convalescent) sample time points were stimulated, and degranulation was assessed via surface staining for CD107a. Data are pooled from 2 independent experiments. Primary infected individuals were compared with previously exposed individuals in A and acute samples versus convalescent samples in B. (C–E) PBMCs isolated from healthy donors (n = 11) stimulated with antibody-depleted plasma pools from the acute or convalescent time points for primary infected and previously exposed individuals. A ratio indicating geometric mean fluorescence intensity surface expression changes is shown for classical monocytes (C), intermediate monocytes (D), and nonclassical monocytes (E). Data were pooled from 2 independent experiments. Statistical analysis in A was done using a mixed effects model matched on donor, followed by Šídák’s post hoc test to correct for multiple comparisons. Statistical analysis in B was calculated using 2-tailed matched pair 2-way ANOVA followed by Šídák’s post hoc test for multiple comparisons. Statistical analyses in C–E was done using 2-tailed Student’s t tests; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. See also related Supplemental Figures 2 and 3. Data represent individual donors.