Antibodies elicited by a late liver stage-arresting but not early liver stage-arresting GAP recognize antigens of both late liver stages and blood stages.
C57BL/6 mice were immunized twice with 50,000 LAGAP or EAGAP sporozoites. Serum was collected prior to immunization (“pre-immune”) and two weeks after the last immunization for use in immunofluorescent assays (IFA) against parasite life cycle stages. IFAs were performed using fixed salivary gland sporozoites (A), liver sections of infected mice obtained at 12, 24, 33 and 48 hours post-infection (B) and blood stages (C). Parasites were also visualized using antibodies recognizing binding immunoglobulin protein (BiP) and MSP1 (for 48h liver stages and BSs). DNA was visualized with 4',6-diamidino-2-phenylindole (DAPI). These data indicate that antibodies in LAGAP-immunized C57BL/6 mice recognize all parasite life stages whereas EAGAP immune serum only recognizes sporozoites/early liver stages. Scale bar: 10 μm.