Fig. 2

Limited evidence for complement C5-9 fixation and MAC activity on the surface of CS2 pRBCs. A Complement C5-9 fixation on CS2 pRBCs was tested by flow cytometry following opsonization with either antibodies from a subset of 7 PNG donor samples (with moderate to high C1q/C3 fixing activity on CS2 pRBCs) or 6 Australian malaria non-exposed donors in the presence of NS. Complement fixation is presented as the average gMFI of each sample tested in duplicate and the red line represents the median gMFI for all samples tested in each category. B Correlation between complement C5-9 fixation and C1q/C3 fixation tested on a subset of 7 PNG donor samples (with moderate to high C1q/C3 fixing activity on CS2 pRBCs). C Complement-mediated pRBC killing/lysis was examined by culturing CS2 pRBCs opsonized with antibodies from PNG pregnant women (n=7) in the presence of normal serum, heat-inactivated serum or no-added serum, and measuring parasitemia by flow cytometry after two growth cycles. Data are presented as the average parasitemia of each sample run in triplicate over 3 independent experiments. The dotted red line represents the median parasitemia of CS2 pRBCs cultured in the absence of either PNG or Australian malaria non-exposed antibodies and NS or HIS. Comparisons were made using Mann-Whitney U test.