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Fig. 2 | Malaria Journal

Fig. 2

From: Red blood cell blood group A antigen level affects the ability of heparin and PfEMP1 antibodies to disrupt Plasmodium falciparum rosettes

Fig. 2

An improved flow cytometric method for measuring P. falciparum absolute rosetting rate and relative rosette size. A Parasite cultures were co-stained with Hoechst and Dihydroethidium (DHE) to differentiate uninfected RBCs from Hoechst positive ring and double positive late stage parasite (trophozoite and schizonts) infected RBCs in untreated (left panels), 10 µg/mL heparin-treated (middle panels) and low rosetting UKM74 (right panels) samples. B The percentage of multiplets of late parasite stage was determined by gating for events that did not have a proportional forward scatter area (FSC-A) to forward scatter height (FSC-H) ratio based on C the uninfected RBCs from the same samples. D The percentage of multiples from FCR3S1.2 (± 10 or 100 µg/mL heparin), PAvarO, UCM 83, UKM104 parasite cultures with variable RR was correlated to RR determined by microscopic enumeration of 150–200 iRBCs using Spearman’s rank correlation coefficient. E FCR3S1.2 parasites were grown in the blood of seven donors from each blood group and treated with heparin prior to flow cytometry. Percentage of multiplets upon addition of heparin in BgO (crosses), BgA (circles), BgB (squares) and BgAB (triangles) (mean ± SD). F Multiplets relative mean side scatter area (SSC-A) was correlated to the rosette sizes determined under the microscope by counting the mean number of RBC bound to iRBC (100 iRBCs/sample). Correlation was measured using Spearman’s rank correlation coefficient. All samples were normalized to the mean SSC-A in BgO, which was set as 1. G FCR3S1.2 parasites were grown in the blood of seven donors from each blood group and treated with heparin prior to flow cytometry. Relative multiplet size (SSC-A) upon addition of heparin in BgO (crosses), BgA (circles), BgB (squares) and BgAB (triangles) (mean ± SD). The mean SSC-A without heparin was set as 1 for each blood group

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