Correlation between rosetting and heparin binding of 3 different Plasmodium populations.

(A) Rosetting rates (▪) and heparin–FITC binding rates (□) for FCR3S1 and 2 clonal populations, the high rosetting clone FCR3S1.2 and the low rosetting clone FCR3S1.6. Rates were determined as described in “Materials and methods.” (B) Competition of heparin–FITC binding to living cultures of FCR3S1.2 by heparin (—•—), HS (—○—), and CSA (—◊—). (C) Sensitivity of rosetting (—▪—) and FITC-heparin-binding (—◊—) of FCR3S1.2 cultures to trypsin treatment as indicated in “Materials and methods.” All results are shown as mean and standard variation from 3 separate experiments.