FIG 5.
CS2-SBP1-KO parasites induce higher levels of cytokines and chemokines from primary human monocytes than do CS2-WT parasites. (A and B) Monocytes from naive human donors were stimulated for 12 h with uRBCs, CS2-WT iRBCs, and CS2-SBP1-KO iRBCs (n = 11 donors) (A) or uRBCs, 3D7-WT iRBCs, and 3D7-UpsCR iRBCs (n = 10 donors) (B). Concentrations of cytokines and chemokines in culture supernatants were measured by a multiplex ELISA. Data shown are those after subtraction of the uRBC background, and connecting lines indicate paired WT- and mutant iRBC-stimulated samples. Different donors were used for the data in panels A and B. Paired t tests were performed, with a P value of <0.05 being considered significant. (C) Cells from three donors stimulated as described above for panel A were lifted, attached to slides by cytospinning, fixed, and Field stained. Slides were analyzed by light microscopy, and cells showing phagocytosis of iRBCs or hemozoin were counted. A minimum of 300 cells was counted under each condition; cell numbers were normalized and are displayed as proportions of the total cells counted. Error bars represent standard errors of means. Paired t test showed no significant difference in phagocytosis rates.