Switching of stevor expression in B3B1 results in increased erythrocyte rigidity. (A,C) Retention rate of erythrocytes infected with B3 (gray bar) and B3B1 before (B3B1 OFF, red bar) or after (B3B1 ON, green bar) switching in stevor gene family expression. Measurements were performed on 2% hematocrit cultures containing 2% to 10% tightly synchronized parasites at 34 hpi. (B,D) LORCA rigidity measurements of erythrocytes infected with B3 (gray bar) and B3B1 before (B3B1 OFF, red bar) or after (B3B1 ON, green bar) switching in stevor gene family expression. Measurements were performed on MACS-concentrated cultures containing 50% synchronized parasites at 34 hpi. (E) Analysis of transcriptional levels for the stevor gene family in B3B1 line before (B3B1 OFF, red bars) and after (B3B1 ON, green bars) switching in expression. Transcriptional analysis was performed at 26 to 28 hpi during the same life cycle as the LORCA and microsphere matrix measurements. Transcription levels were normalized to the transcription level of the seryltRNA synthetase housekeeping gene (PF07_0073).