Transcripts of var2csa (PFL0030c) constituted 7% of total measured var gene transcripts in unselected 3D7 parasites, increasing to 80% after seven rounds of PAM1·4 selection. In contrast, PAM8·1 selection did not affect the proportion of var2csa transcripts in 3D7 (Figure 1g ). The HB3 genome contains two var2csa paralogs, var2csa-A and var2csa-B (13) . In unselected HB3 parasites, var2csa-A transcripts constituted 1% of the measured var transcripts, increasing to 28% and 4% after seven rounds of selection by PAM1·4 and PAM8·1, respectively (Figure 1h ). Transcript levels of the var2csa-B gene increased from 23% to 57% and 92% after seven rounds of selection by PAM1·4 and PAM8·1, respectively (Figure 1h ). No var transcript other than a Human monoclonal VSA PAM -specific antibody used for selection. b Determination of sex-specificity involves a two-step procedure: first establishment that IE surface-reactive IgG levels in at least one of the three donor categories (exposed multigravidae, exposed men, and unexposed controls) differs from at least one other category. Only if this is the case (as it was here: P < 0·001 in all cases), can sex-specificity be confidently assessed by post hoc testing for significant (P < 0·05) pair-wise differences. The result of this post hoc testing is indicated here as No: none of the two post hoc criteria for sex-specificity were met, Indeterminate: only one of the criteria was met. Yes: both criteria were met. See Materials and Methods for further details.