Fig. 3: Effect of RBK21 on NK cell function.
From: RIFINs displayed on malaria-infected erythrocytes bind KIR2DL1 and KIR2DS1
a, GFP expression in KIR2DL1-reporter cells upon stimulation with iRBCs infected with parental 3D7 cells (left) or the RBK21-expressing parasite line (right). The percentage of GFP-positive cells is shown. b, KIR2DL1-positive NK cells gated using anti-KIR2DL1/DS1 and anti-KIR2DL1/DS5 antibodies for c–e. c–e, Suppression of CD107a expression (c), IFNγ production (d) and TNF production in KIR2DL1+ NK cells by K562 cells, which express RBK21, with K562 parental cells or K562 expressing a non-KIR2DL1-binding RIFIN (ctl-RIFIN; PF3D7_1254200) as negative controls (e). Lines show the mean (n = 9 independent measurements from one donor) with ****P < 0.0001 (two-sided Student’s t-test). Equivalent analysis of cells from a different donor is shown in Extended Data Fig. 6a. f, Effect of K562 cells expressing RBK21 on the cytotoxic activity of NKL cells (purple) or NKL cells expressing either KIR2DL1 (blue) or KIR2DL3 (green), assessed at four ratios of target to effector cells. Data represent the mean ± s.d. (n = 3 biologically independent samples) with ****P < 0.0001, ***P < 0.001 and **P < 0.01 (two-sided Student’s t-test). g, Analysis of localization of RIFINs (pink) or perforin (green) in contact areas for NK cells on SLBs coated with RIFIN Pf3D7_1254800, RBK21 or RBK21S221R, showing representative images. h,i, Quantification of perforin (h) and RIFIN (i) in contact areas from g. Measurements from three independent donors with control (n = 43 cells), Pf3D7_1254800 (n = 28 cells), RBK21 (n = 31 cells), RBK21S221R (n = 29 cells) and KEN-01 (n = 63 cells). Each data point represents a measurement from one cell. Dunn’s multiple comparison test (h) and Tukey’s multiple comparison test (i) were performed. *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001. Exact P values in source data. Scale bar, 10 μm.
