Timing of VAR2CSA surface expression. Surface staining of infected erythrocytes selected with VAR2CSA-specific rabbit antibodies, NF54VAR2CSA, and the unselected control, NF54. The median of FITC fluorescence as measured by flow cytometry is shown for each serum sample. Pools of human sera from P. falciparum exposed females and males, and unexposed Danes (DK-pool) were used as primary antibodies. VAR2CSA expression was confirmed by staining with VAR2CSA DBL5ε-specific rabbit antibodies and irrelevant rabbit immune serum was used as negative control. Samples were processed and run simultaneously at individual time points.