Fig. 2

Uptake ability was dependent on the sample preparation method. a–c Western blotting analysis of human and parasite proteins. a Lysates prepared from iRBCs cultured in PDS- and naturally coagulated serum (NCS)-containing culture media. Samples were collected using the Percoll method and were treated with saponin. Band 3, β-actin, SERA5, and EXP2/3C were used as internal controls. b Protease protection assay in the RBC and PV lysates prepared from iRBCs cultured in PDS-containing culture medium. Samples were collected using the Percoll method and were treated with streptolysin O. “+” and “−” indicate treatment with or without proteinase K, respectively. Band 3, β-actin, SERA5, and EXP2/3C were used as internal controls. c (left panels) Serum proteins in the iRBC lysates cultured in PDS- and NCS-containing culture media. Samples were collected using the precipitation method and were treated with saponin. (right panels) Serum proteins in the original sera, PDS, and NCS. SERA5 was used as internal control. The asterisk indicates a non-specific band. d Confocal microscopy images showing the localization of protein S, prothrombin, vitronectin (red), and DNA (cyan) in iRBCs cultured in PDS- or NCS-containing medium. Samples were fixed using the methanol fixation method. As a control, rabbit control IgG was used instead of primary antibodies. The scale bar represents 5 µm. All samples were prepared from 3D7 strain