FIG. 4.
In vitro inhibition of hepatocyte invasion by P. yoelii sporozoites. The inhibitory effect of human anti-LSA3 Abs was evaluated upon P. yoelii or P. berghei sporozoite invasion into mice hepatocytes. Abs were affinity purified on the recombinant protein β-Gal-DG729 (LSA3-Nterm) or β-Gal-DG671 (SALSA). Anti-SALSA Abs (α-SALSA) were used as control for human Abs (α-LSA3). The anti-CS MAb of P. berghei was used as control for the P. berghei sporozoite invasion. The human Abs were tested at a concentration corresponding to their IFAT end point titer (1/2). The anti-CS MAb of P. berghei was used at a dilution of 5 × 10−4 (IFAT end point titer of 10−6). All samples were tested in duplicate. The number of liver schizonts was counted in each well, and the percentage of inhibition was calculated compared to that for control wells to which no Abs were added. The numbers of P. yoelii and P. berghei liver schizonts in control wells without Abs were 101.5 ± 15.45 and 110.5 ± 21.70, respectively.