FIG 5.

P. yoelii lisp2⁻ plasmei2⁻ GAP immunization of BALB/cJ mice elicits humoral responses to multiple life cycle stages. (A to F) IFA was used to determine IgG antibody activity against the parasite from GAP-immunized mice. Sera from pooled mice were diluted 1:200 for IFA, and bound antibody was detected with a fluorescent secondary antibody. (A) Sera from GAP-immunized mice (IgG, top left, in red) but not sera from naive mice (IgG, top right) recognize the sporozoite surface. Differential interference contrast images of the sporozoites are shown in the bottom images. (B to D) Liver stage IFAs using GAP-immunized sera (shown in red) show liver stage peripheral and internal reactivities at 24 (B), 34 (C), and 44 (D) h of development. At 52 h (E), sera recognize the surface of exoerythrocytic merozoites in a segmenting schizont, magnified for clarity in panel F. The parasite was visualized with antibody to BiP (shown in green) and DNA in blue. Scale bar: 10 μm.