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Characterization of Platelet factor 4-Polyanion complexes and corresponding pathogenic antibodies

血小板因子 4-聚阴离子复合物和相应致病性抗体的表征

基本信息

批准号：
269095734
负责人：
Dr. Thi Huong Nguyen, Ph.D.
金额：
--
依托单位：
Institut für Bioprozess- und Analysenmesstechnik e.V.
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/269095734?language=en
关键词：
Characterization Platelet factor Polyanion complexes

项目摘要

After we have successfully characterized biophysical properties of anti-PF4/polyanion antibodies (aPF4/P Abs), which induce the adverse drug effect heparin-induced thrombocytopenia (HIT), we now aim to build on this information to further understand the pathogenesis of HIT. We have shown in our previous proposal that clinically relevant aPF4/P Abs have a higher binding affinity to PF4/heparin complexes than clinically non-relevant Abs, we now aim to widely investigate the interaction of Abs to PF4/P complexes using different physicochemical environments and mutated/recombinant PF4s. As second approach, we want to establish a detection method for aPF4/P Abs using a cell membrane mimicking system because the clinically relevant Abs bind with much higher avidity to PF4/P complexes on cell membranes than clinically non-relevant antibodies. With both approaches we aim to establish a tool to differentiate clinically relevant (platelet activating) and non-relevant aPF4/P Abs, which can be further developed for clinical application.Monoclonal antibodies are very helpful tool for pathogenicity studies, but the two available monoclonal antibodies mimicking human aPF4/P Abs, namely KKO and 5B9 are not well-characterized in comparison to patient-derived antibodies. With the tools we have developed during the last 3 years, we aim to characterize both monoclonal Abs in comparison to human, patient-derived aPF4/P Abs to facilitate interpretation of future in vitro and in vivo studies (animal studies) with these antibodies.In the third part of our proposal we address the pathogenesis of HIT. We build on the observation that PF4 binds to von Willebrand factor which opens the possibility that aPF4/P Abs interfere with von Willebrand factor cleavage by ADAMTS13 causing thrombotic microangiopathy. Based on our clinical observations, we assume that autoimmune group-3 antibodies interfere with ADAMTS 13 cleavage of von Willebrand factor, as patients with these antibodies show symptoms of thrombotic microangiopathy. Closely linked to this question is the final part of this proposal in which we aim to further investigate the mechanisms by which aPF4/P Abs interfere and activate endothelial cells.Taken together, this proposal will provide deeper understanding on the pathogenesis of HIT, and may provide the basic information to solve one of the most important clinical issues associated with HIT, i.e. improving the specificity of tests applicable in the clinical laboratory for clinically relevant aPF4/P Abs.

在我们成功地表征了抗PF4/多阴离子抗体(aPF4/P-Abs)的生物物理特性后，我们现在的目标是基于这些信息来进一步了解HIT的发病机制。我们在以前的研究中已经证明，临床相关的aPF4/P抗体与PF4/肝素复合体的结合亲和力高于临床无关的抗体，现在我们的目标是利用不同的物理化学环境和突变/重组的PF4来广泛研究抗体与PF4/P复合体的相互作用。作为第二种方法，我们希望建立一种使用细胞膜模拟系统检测a-PF4/P抗体的方法，因为与临床相关的抗体与细胞膜上的PF4/P复合体结合的亲和力比临床无关抗体高得多。通过这两种方法，我们的目标是建立一种工具来区分临床相关的(血小板激活)和不相关的aPF4/P抗体，以便进一步开发用于临床应用。利用我们在过去三年中开发的工具，我们的目标是将这两种单抗与人、患者来源的aPF4/P抗体进行比较，以便于解释未来使用这些抗体进行的体外和体内研究(动物研究)。在我们的建议的第三部分，我们解决HIT的发病机制。我们建立在观察到PF4与von Willebrand因子结合的基础上，这开启了aPF4/P抗体干扰ADAMTS13裂解von Willebrand因子导致血栓性微血管病变的可能性。根据我们的临床观察，我们假设自身免疫组-3抗体干扰ADAMTS 13对von Willebrand因子的裂解，因为这些抗体的患者表现出血栓性微血管病变的症状。与这个问题密切相关的是这一建议的最后部分，我们旨在进一步研究aPF4/P抗体干扰和激活内皮细胞的机制。综上所述，这一建议将使人们对HIT的发病机制有更深入的了解，并可能为解决与HIT相关的最重要的临床问题之一提供基础信息，即提高临床实验室适用于临床相关aPF4/P抗体检测的特异性。

项目成果

期刊论文数量（13）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Physicochemical Characteristics of Platelet Factor 4 under Various Conditions are Relevant for Heparin-Induced Thrombocytopenia Testing.

DOI：
10.1021/acs.jpcb.9b11695
发表时间：
2020-01
期刊：
The journal of physical chemistry. B
影响因子：
0
作者：
V. Bui;Patrycja Gebicka;Holger Hippe;R. Raschke;Thuy-Linh Nguyen;A. Greinacher;Thi‐Huong Nguyen
通讯作者：
V. Bui;Patrycja Gebicka;Holger Hippe;R. Raschke;Thuy-Linh Nguyen;A. Greinacher;Thi‐Huong Nguyen

Effect of pH and ionic strength on the binding strength of anti-PF4/polyanion antibodies