FIG. 1.

(A) Silver stained 10 to 20% gradient SDS-PAGE gel of solubilized sporozoites (10⁷) before (lane 3), and after (lane 2) MAb C6B6 affinity chromatography purification of P23 (1 μg). Lane 4 contains solubilized oocysts (2.5 × 10⁶) for comparison. Lane 1 was loaded with sample buffer to identify silver stain artifacts. Molecular mass standards (Bio-Rad) are indicated on the left (phosphorylase B, 97.4 kDa; BSA, 66.2 kDa; ovalbumin, 45 kDa; carbonic anhydrase, 31 kDa; and soybean trypsin inhibitor, 21.5 kDa). (B) Western blot recognition of affinity-purified P23 (lane 1) (1 μg) and a comigrating 23-kDa antigen in whole sporozoites (lane 2) (4 × 10⁶) by MAb C6B6. Lane 3 (1 μg of P23) and lane 4 (4 × 10⁶ sporozoites) were probed with isotype control MAb. Molecular mass standards (Amersham Pharmacia Biotech, Arlington Heights, Ill.) are indicated on the left (myosin, 200 kDa; β-galactosidase, 97.4 kDa; BSA, 69 kDa; carbonic anhydrase, 46 kDa; soybean trypsin inhibitor, 30 kDa; lysozyme, 21.5 kDa; and aprotinin, 14.3 kDa).