Figure 4. Characterization of collagen binding induced A1 conformational change by antibodies.

(A) Normalized A1 site densities detected by conformation specific anti-A1 mAbs. The ligand site densities for pVWF and A1 were measured by flow cytometry using 5D2 (m₁^5D2), then normalized by the site densities measured with conformation-independent 6G1 (m₁^6G1). The data were presented as m₁^5D2/m₁^6G1 in percentage. (B) Conformations probed by mAb coated targets. Adhesion frequencies (P_a) between the 5D2 or 6G1 coated target and probes coated with A1 or pVWF. (C) The effective binding affinities of pVWF and 1238-A1 to 6G1 by converting P_a^6G1 (from panel B) to [-ln(1 - P_a^6G1)/ m₁^6G1]. The same keys were used as Fig. 1G.