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. 2019 Jun 10;17(6):e3000308. doi: 10.1371/journal.pbio.3000308

Fig 1. Phosphatases treatment decreases rVAR2CSA and IE cytoadhesion under static and flow conditions.

Fig 1

(A) 7G8CSA or FCR3CSA IEs at trophozoite mid and late stages pretreated or not for 30 min with 0.1 units of PP1or PP2a were assayed for binding on a monolayer layer of BeWo cells or on CSA-coated plastic spots. Bound IEs were counted in 5 random fields, and results were expressed as percentage of inhibition compared to buffer-treated IEs (100% binding/0% inhibition). (B) Typical images of a field showing IEs bound to BeWo cells or to CSA-coated plastic. (C) NF54CSA or FCR3CSA IEs pretreated or not with both phosphatases were assayed for adhesion on decorin-coated Vena8 Endothelial+ biochips. A shear stress of 0.05 Pa was applied for 5 min. Numbers of adherent IEs were counted in 5 positions in the channel, and results were expressed as percentage inhibition compared with untreated IEs (100% binding). (D) Binding of recombinant VAR2CSA pretreated or not with increasing units of PP1 or PP2a was monitored using an ELISA-based direct binding assay with coated decorin. Error bars correspond to SD between 4 independent experiments. Each experiment was performed in duplicate. Numerical values that underline the graphs are shown in S1 Data. BeWo, human placenta choriocarcinoma; CSA, chondroitin sulfate A; ELISA, enzyme-linked immunosorbent assay; IEs, infected erythrocytes; PP1, protein phosphatase 1; PP2a, protein phosphatase 2a; rVAR2CSA, recombinant VAR2CSA. NF54, Plasmodium falciparum strain NF54; NF54CSA, Plasmodium falciparum strain NF54 selected for CSA adhesion; FCR3, Plasmodium falciparum strain FCR3; FCR3CSA, Plasmodium falciparum strain FCR3 selected for CSA adhesion; 7G8, Plasmodium falciparum strain 7G8; 7G8CSA, Plasmodium falciparum strain 7G8 selected for CSA adhesion.