Immobilized streptococcal M proteins support platelet adhesion and thrombus formation under flow.
(A) Schematic representation of 3 streptococcal proteins. The variant M5ΔB lacks the fibrinogen-binding B repeats. (B) Sodium dodecyl sulfate–polyacrylamide gel electrophoresis of the recombinant proteins used to coat glass coverslips at a concentration of 100 μg/mL, visualized with Coomassie blue (stain) and radiolabeled fibrinogen binding (blot). (C) Single platelets and thrombi on an area of 45 000 μm2 after blood perfusion (donor 2) over the 3 different M proteins for 8 minutes at 1500 s−1. (D) Measurement of surface coverage by single platelets and thrombi after 8 minutes of perfusion at the indicated wall shear rates. The results shown are the average of 3 (rM1) or 2 (rM5 and rM5ΔB) experiments with blood from different donors; bars show the range of values observed.
