Adhesion of activated SS RBCs to ECs is mediated through the LW receptor. Inhibition of adhesion with antibody and recombinant protein was performed as described in “Materials and methods,” using EC-RF24 (A) and HUVECs (B-C). For all experiments, SS RBC controls were sham treated as described in “Materials and methods.” Results are presented as percent of cells adherent at a shear stress of 2 dynes/cm2 (n = 3 for A-C). (A) SS RBCs activated with 0.2 mM IBMX + 176 μM db-cAMP were incubated without mAb, with 10 μg/mL anti-LW, or with 100 μg/mL anti-CD47 mAb IgG, and then washed before adhesion assays were performed. (B) SS RBCs were incubated without mAb, with 10 μg/mL anti-LW, or with 100 μg/mL anti-CD47 mAb, washed, treated with 20 nM epinephrine for 1 minute, and then washed before adhesion assays were performed. (C) Confluent cultures of HUVECs were incubated without recombinant protein or with 25 μg/mL recombinant LW-Fc or CD44-Fc protein, washed, and then tested for their ability to support adhesion of sham-treated SS RBCs or SS RBCs treated with 20 nM epinephrine for 1 minute. In panels A through C, error bars show SD.
