var2csa showed marked changes, and var2csa was therefore the dominant transcript in all the parasites following antibody selection. The dominance of var2csa-B transcripts relative to var2csa-A in HB3 after PAM8·1 selection, suggested that the DBL3-X domain in the protein encoded by var2csa-B might be of the FCR3-type recognized by PAM8·1, whereas the corresponding domain encoded by var2csa-A might be of the 3D7-type (PFL0030 c) not recognized by PAM8·1 (2).