Hematological Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway.
Thromb Res. 2012 Sep;130(3):538-46. doi: 10.1016/j.thromres.2012.06.001. Epub 2012 Jun 23.
Tissue factor (TF), the primary initiator of coagulation in vivo, plays a major role in both thrombosis and hemostasis. The expression of TF in monocytes is well documented, but its presence in other blood cells has been disputed, possibly due to methodological variations among different studies.
We studied TF expression on platelets, monocytes, lymphocytes and microparticles (MPs) by flow cytometry (FCM) with five commercially available mouse anti-human TF antibodies (HTF-1, TF9-10H10, CLB/TF-5, VIC7 and VD8). The ability of different TF antibodies to inhibit cell surface TF activity was explored by incubating LPS-stimulated monocytes and MPs derived from LPS-stimulated monocytes (MMPs) with TF antibodies followed by measuring TF activity.
HTF-1 detected TF only on LPS-stimulated monocytes, whereas, TF9-10H10 and VD8 detected TF associated with MPs and MMPs in addition to LPS stimulated monocytes. Surprisingly, CLB/TF-5 and VIC7 detected TF on platelets, monocytes even under unstimulated conditions, in addition to MPs and MMPs. CLB/TF-5 also detected TF on unstimulated lymphocytes. Inhibitory studies showed that at a final concentration of 10 μg/mL, HTF-1, CLB/TF-5 and VD8 inhibited monocyte TF activity by 81-84% and MMP TF activity by 92-96%; whereas TF9-10H10 had no inhibitory effect on TF activity in monocytes and MMPs.
Our results suggest non-specific binding by the CLB/TF-5 and VIC7 antibodies in a FCM test system and explain at least some of the reports on TF presence in blood cells, particularly TF associated with platelets and MPs. TF9-10H10 and VD8 are more suitable to detect TF on MPs by FCM.
组织因子（TF）是体内凝血的主要启动因子，在血栓形成和止血中都发挥着重要作用。单核细胞中 TF 的表达已得到充分证实，但在其他血细胞中的存在存在争议，这可能是由于不同研究之间的方法学差异所致。
我们通过流式细胞术（FCM）使用五种市售的抗人 TF 抗体（HTF-1、TF9-10H10、CLB/TF-5、VIC7 和 VD8）研究了血小板、单核细胞、淋巴细胞和微颗粒（MPs）上的 TF 表达。通过孵育 LPS 刺激的单核细胞和来自 LPS 刺激的单核细胞的 MPs（MMPs）与 TF 抗体，然后测量 TF 活性，研究了不同 TF 抗体抑制细胞表面 TF 活性的能力。
HTF-1 仅在 LPS 刺激的单核细胞上检测到 TF，而 TF9-10H10 和 VD8 除了 LPS 刺激的单核细胞外，还在 MPs 和 MMPs 上检测到与 TF 相关的物质。令人惊讶的是，CLB/TF-5 和 VIC7 在未刺激条件下，除 MPs 和 MMPs 外，还在血小板和单核细胞上检测到 TF。CLB/TF-5 还在未刺激的淋巴细胞上检测到 TF。抑制研究表明，在终浓度为 10μg/mL 时，HTF-1、CLB/TF-5 和 VD8 抑制单核细胞 TF 活性 81-84%，抑制 MMP TF 活性 92-96%；而 TF9-10H10 对单核细胞和 MMPs 中的 TF 活性没有抑制作用。
我们的结果表明，在 FCM 测试系统中，CLB/TF-5 和 VIC7 抗体存在非特异性结合，并解释了至少部分关于血细胞中 TF 存在的报告，特别是与血小板和 MPs 相关的 TF。TF9-10H10 和 VD8 更适合通过 FCM 检测 MPs 上的 TF。
