Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan, ROC.
J Infect. 2012 Mar;64(3):325-34. doi: 10.1016/j.jinf.2011.11.023. Epub 2011 Nov 25.
Dengue virus (DENV) infection may result in severe dengue hemorrhage fever (DHF). However the mechanisms to cause hemorrhage during DENV infection are not fully understood. The sera level of secreted DENV nonstructural protein 1 (NS1) is correlated with the development of DHF. However, whether secreted NS1 can interfere with coagulation and contribute to the hemorrhage in DHF is unknown. Since thrombin plays a very important role in the activation of coagulation, we investigated whether NS1 can bind to thrombin and affect its formation or activity.
We first demonstrated that NS1 could bind to thrombin and formed NS1/thrombin complex in dengue patients' sera by enzyme-linked immunosorbent assay (ELISA). The ability of NS1 binding to prothrombin or thrombin was further confirmed using recombinant NS1 (rNS1) by ELISA, co-immunoprecipitation, and rNS1-affinity column purification. Even though the binding of rNS1 to thrombin showed no effect on thrombin activity, rNS1 could inhibit prothrombin activation and prolong activated partial thromboplastin time (APTT) of human platelet poor plasma.
These results suggest secreted DENV NS1 may bind to prothrombin and inhibit it activation, which in turn, may contribute to the APTT prolongation and hemorrhage in DHF patients.
登革病毒（DENV）感染可能导致严重登革热出血热（DHF）。然而，导致 DENV 感染时出血的确切机制尚不完全清楚。血清中分泌的 DENV 非结构蛋白 1（NS1）水平与 DHF 的发生相关。然而，分泌的 NS1 是否可以干扰凝血并导致 DHF 出血尚不清楚。由于凝血酶在凝血激活中起着非常重要的作用，我们研究了 NS1 是否可以与凝血酶结合并影响其形成或活性。
我们首先通过酶联免疫吸附测定（ELISA）证明 NS1 可以与登革热患者血清中的凝血酶结合形成 NS1/凝血酶复合物。通过 ELISA、共免疫沉淀和 rNS1 亲和柱纯化，进一步证实了 NS1 与凝血酶原或凝血酶的结合能力。尽管 rNS1 与凝血酶的结合对凝血酶活性没有影响，但 rNS1 可以抑制凝血酶原的激活并延长人血小板缺乏血浆的活化部分凝血活酶时间（APTT）。
这些结果表明，分泌的 DENV NS1 可能与凝血酶原结合并抑制其激活，这可能导致 DHF 患者的 APTT 延长和出血。
