Generation and characterization of chimeric mice that lack VWF in either megakaryocytes or endothelial cells. MNCs, isolated from donor WT (black) or VWF KO mice (white), were transplanted into lethally irradiated VWF KO or WT acceptor mice to generate (A) chimeric mice that have VWF only in platelets (VWF PLT) or (B) chimeric mice that specifically lack VWF in their platelets (VWF EC), respectively. (C) Relative amount of VWF-positive platelets detected in WT (n = 17), VWF KO (n = 12), VWF PLT chimeric (n = 18), and VWF EC chimeric (n = 14) mice. (D) VWF antigen (Ag) levels (VWF:Ag) were determined in plasma samples from WT (n = 16), VWF KO (n = 14), VWF PLT chimeric (n = 21), and VWF EC chimeric (n = 8) mice. (E) FVIII activity (FVIII:C) was determined in plasma samples from WT (n = 12), VWF KO (n = 12), VWF PLT chimeric (n = 16), and VWF EC chimeric (n = 10) mice. Results are expressed as percentage of WT values. ns, not statistically significant. ***P < .001.