Fig. 2: RBC agglutination is not directly correlated with enhanced P. falciparum invasion.

a Gating strategy for flow cytometry analysis of RBC clusters events from a representative experiment. RBC agglutination/clustering of three cells or more is denoted as “Clusters” in orange. b RBCs were treated with 25 µg/ml anti-CD44 monoclonal antibodies or 2 µM RII EBA-175 and assessed for agglutination/clustering by flow cytometry, measured by forward scatter (size). Frequency of cluster events from three donors with average ± SD is shown. Statistical analysis: Kruskal-Wallis with FDR correction; * p = 0.0468, ** p ≤ 0.01. c Representative images of RBCs treated with 25 µg/ml anti-CD44 monoclonal antibodies (BRIC 222, IM7, BRIC 235, KZ1) or 2 µM RII EBA-175, taken with 20X objective. d RBCs were treated with 25 µg/ml of the indicated monoclonal antibodies or their respective F(ab)s. Average frequency of cluster events from 5 donors (No Ab, BRIC 222 F(ab)) or 6 donors (BRIC 222, KZ1, KZ1 F(ab)) ± SD is shown. Statistical analysis: Kruskal-Wallis with FDR correction; *** p = 0.0006. e The relative invasion efficiency within populations of “Clusters” or “Single cells” was measured by flow cytometry and normalized to the mean of the no antibody (No Ab) condition. Each dot represents an individual biological replicate (N = 4 biological replicates; n = 3 technical replicates). Error bars represent SEM. Statistical analysis: paired t-test, one-tailed; ** p = 0.0069, * p = 0.0112.