Figure 4

Fluorochrome labeled beads and anti-MSP-1p42 antibodies enter viable pRBC and gain access to the intra-erythrocytic parasites. (A) 3D7 or FVO parasite cultures (2% hct, 2–3% parasitaemia) were incubated with either Fluorescein-labeled beads or 10% Alexa 488-conjugated anti-MSP-1p42 immunoglobulins (Igs). Igs were purified from rabbit sera after immunization with MSP-1p42(FVO) (FMP003) emulsified in FA. Igs were tested at the same titer as serum assay. (B) same as for panel A, except that pRBCs were incubated with either Alexa 488-labeled Igs derived from rabbits either immunized with reduced/alkylated MSP-1p42 (negative control) or MSP-1p42(FVO) (FMP003) emulsified in FA. The confocal microscopy images were recorded at either 3% laser power (same power as the images in Panel A) or at 95% laser power (highest laser sensitivity). The center column shows the bright field image of the left column.