FIG. 3.

Western blot analyses of P. berghei antigen and immune sera raised against nontransformed (2.33) and transformed (Pb233/221) P. berghei clones. (A and B) Antigen preparations were obtained from ookinete cultures, nontransformed parental P. berghei blood-stage parasites (non-gametocyte-producing clone 2.33 and gametocyte-producing clone HP), or transformed Pb233/221 and PbHP/221 blood-stage parasites (expressing transgenic Pbs21) and separated on an SDS–14% PAGE gel (C) recombinant Pbs21 was separated on an SDS–12% PAGE gel under nonreducing conditions and transferred to a nitrocellulose membrane. Pbs21-specific MAbs recognizing conformation-independent (MAb 13.1) or conformation-dependent (MAbs 17.9 and 12.1) epitopes were used. (A) Lane 1, whole ookinete culture homogenate (ca. 5 × 10⁴ ookinetes) containing asexual, sexual, and ookinete-stage proteins probed with MAb 13.1; lane 2, clone 2.33 homogenate (ca. 5 × 10⁷ parasites) probed with MAb 13.1; lanes 3 to 6, Pb233/221 homogenate (ca. 5 × 10⁷ parasites) probed with MAb 13.1, MAb 17.9, MAb 12.1, and NMS, respectively; lane 7, HP homogenate (ca. 5 × 10⁷ parasites) probed with MAb 13.1; lane 8, PbHP/221 homogenate (ca. 2 × 10⁷ parasites) probed with MAb 13.1. (B) Lanes 9 to 12, whole ookinete homogenate probed with MAb 13.1, NMS, anti-2.33 immune serum, and anti-Pb233/221 immune serum, respectively. (C) Lanes 13 to 16, affinity-purified recombinant Pbs21 (aa 1 to 188) probed with MAb 13.1, NMS, anti-2.33 immune serum, and anti-Pb233/221 immune serum, respectively.