Fig 7.

Binding of PvMSP1P fragments expressed on COS-7 cells to erythrocytes. (A) The transfection efficiency of each plasmid construct was calculated by counting green fluorescent cells (GFP) and COS-7 cells in bright field image (Merge). Average transfection efficiency was more than 80%. (B) Erythrocyte-binding rosettes formed on the surfaces of COS-7 cells expressing PvDBPII or different fragments of PvMSP1P or PvMSP1-19 were visualized under light microscopy. (C) The number of rosettes formed by the COS-7 cells transfected with genes coding for either PvDBPII or different fragments of PvMSP1P or PvMSP1-19. Detection of the transfection efficiency into COS-7 cells of all constructs by counting green signal cells within 30 microscope fields (×200). A positive result was defined as more than half the surface of the transfected cells covered with attached erythrocytes, and the total number of COS-7 cells per coverslip was recorded. Data are shown as the mean number of rosettes of three independent experiments, and the error bar represents ± standard deviation. Statistical differences between PvDBPII and the other proteins are indicated with a single asterisk (P < 0.05) and double asterisks (P < 0.001). Statistical difference between PvMSP1P-19 and PvMSP1-19 is shown with triple asterisks (P < 0.001).