Figure 2

Var gene transcript levels in VAR3-expressing Plasmodium falciparum parasites. Var gene transcript levels relative to the average of two internal control genes before and after antibody selection of P. falciparum (a) 3D7 and (b) IT/FCR3 parasites, using Dynabeads coated with rabbit IgG specific for VAR3 PfEMP1. The average of control gene transcript levels is set to 100. The distribution of var transcripts before and after selection is also shown (circular diagrams). Transcript levels were measured by quantitative PCR using a set of primers that amplify 59 and 56 var genes from clone 3D7 and IT/FCR3, respectively. A cross-intron primer specific for the clone 3D7 var3 genes, PFI1820w and PFF0020c, and the clone IT/FCR3 var3 gene, IT4var03, showed similar transcript level as the corresponding exon 1 primer pairs (Table 1). The grouping of var genes are as previously described [16, 17, 23].