Microlyse binds to VWF on the surface of cultured endothelial cells under flow. (A) Binding of Microlyse #1 and #2 (62.1 nM) to VWF on histamine-stimulated endothelial cells under flow. Endothelial cells were stained after fixation with DAPI (blue), and platelets were stained with anti-GPIbα-APC (red). VWF and Microlyse variants were stained with specific antibodies (green). tPA or caplacizumab* were coupled to Alexa488 (green). Images are representative of 3 separate experiments. (B) Binding of Microlyse variants to platelets in ristocetin-treated whole blood, determined by flow cytometry. Data represent the mean ± SD of 3 separate experiments, each performed in duplicate.