SDS-PAGE analysis of purified Abs and diabody. (A) Purified anti-MSP1₁₉ mouse IgG2b (lanes 1, 4, 7, and 10), human IgG1 (lanes 2, 5, 8, and 11), and human IgA1 (lanes 3, 6, 9, and 12) were subjected to SDS-PAGE under nonreducing (lanes 1-3 and 7-8) or reducing (lanes 4-5 and 10-12) conditions on 8.2% polyacrylamide gels, and stained with Coomassie blue (lanes 1-6) or immunoblotted (lanes 7-12). (B) The Abs detect recombinant GST-MSP1₁₉ fusion protein (lanes 1-3) or a fragment of MSP1 in an extract of P yoelii YM merozoites electrophoresed under nonreducing conditions (lanes 4-6) and transferred to nitrocellulose. Detecting Abs: lanes 1 and 4, mouse IgG2b; lanes 2 and 5, human IgG1; and lanes 3 and 6, human IgA1. (C) Purified FcγRI × MSP1₁₉ diabody was run under nonreducing (lanes 1 and 3) or reducing (lanes 2 and 4) conditions. Samples were either blotted and probed with anti-His (lanes 1 and 2) or stained with Coomassie blue (lanes 3 and 4). The diabody detected a blot of recombinant GST-MSP1₁₉ fusion protein run under nonreducing conditions (lane 6). Secondary anti-His Ab did not cross-react with the fusion protein alone (lane 5).