Binding of anti-GPIb mAbs to recombinant GPIbα fragments.

mAbs 6B4 (A), 24G10 (B), TM60 (C), and 27A10 (D) were bound to wild-type and mutated (G233V and M239V) rGPIbα fragments by Biacore. Wild-type or mutated rGPIbα (H1-R280) fragments (100 nmol/L) were injected for 180 seconds, followed by injection of the anti-GPIb mAbs (50 nmol/L) for 180 seconds, and injection of flow buffer thereafter for another 300 seconds. TM60 and 27A10 bound equally well to both mutants. mAb 6B4 had markedly reduced affinity, whereas mAb 24G10 had enhanced affinity.