Complement and CR2/CD21 in the Immune Pathogenesis of HIT

HIT 免疫发病机制中的补体和 CR2/CD21

• 批准号: 10077790
• 负责人: Gowthami M Arepally
• 金额: $ 46.42万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-01-15 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10077790
• 关键词: Allergic Disease; Allergic Reaction; Antibodies; Antibody Formation; Anticoagulants; Antigens; Autoantibodies; Autoantigens; Autoimmune Diseases; B-Cell Antigen Receptor; B-Lymphocytes; Binding; Biological Assay; Blood; Blood Circulation; Blood Platelets; Carbohydrates; Charge; Communicable Diseases; Complement; Complement 3d Receptors; Complement Activation; Complex; Data; Deposition; Development; Disease; Dose; Event; Follicular Dendritic Cells; Funding; Grant; Heparin; Heparin Binding; Humoral Immunities; Hypersensitivity; Immune; Immune response; Immunoassay; In Vitro; Incubated; Individual; Knowledge; Lectin; Leukocytes; Life; Link; Mannose Binding Lectin; Mediating; Mus; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Plasma; Play; Polysaccharides; Predisposition; Proteins; Proteome; Regulation; Role; Sampling; Signal Transduction; Structure; Testing; Thrombosis; Time; Transgenic Organisms; Variant; adaptive immunity; antigen binding; base; ficolin; ficolin-beta; heparin-induced thrombocytopenia; immune activation; immunogenic; immunogenicity; in vivo; novel; recruit; response; sample fixation; seroconversion

ABSTRACT Heparin-induced thrombocytopenia (HIT) is a life-threatening immune-mediated thrombotic disorder caused by antibodies to PF4/heparin complexes. The immune response is common and yet little is understood about its occurrence. In the last funding period, we made fundamental observations related to early events surrounding the host’s encounter with the PF4/heparin antigenic complex. Specifically, we showed: 1) preferential binding of PF4/heparin to circulating B-cells, compared with other leukocytes or platelets, 2) heparin-dependent binding of PF4/heparin to B-cells in patients receiving heparin, 3) complement fixation by PF4/heparin antigen, 4) complement-mediated PF4/heparin binding to circulating B-cells in patients receiving heparin, and 5) binding of complement-coated antigen to B-cells via complement receptor 2 (CR2/ CD21). In the following aims, we will test the hypothesis that complement activation by PF4/heparin complexes and deposition of antigen on B-cells via CD21 is essential for development of HIT autoantibodies. Specific Aim 1: Mechanism of complement activation by PF4/heparin complexes. In preliminary data, we show that mannose-binding lectin and ficolin-2 bind PF4/heparin complexes. Based on these findings, we will test the hypothesis that PF4/heparin complexes activate complement via the lectin pathway. We will define the structural basis of PF4/heparin-lectin interactions, study functional interactions of lectins with PF4/heparin complexes, and examine the role of complement inhibition in HIT. Specific Aim 2: Cellular consequences of CD21 engagement by PF4/heparin and complement. Binding of complement-coated antigen to CD21 augments humoral immunity by 103 to 104 fold. We hypothesize that binding of complement-coated multivalent PF4/heparin to the CD21 complex facilitates recruitment and signaling of antigen-specific B-cells. We will examine downstream signaling, activation and proliferation of cognate and non-cognate B-cells, perform in vivo studies in mice with a fixed B-cell receptor and characterize the contribution of CD21-expressing follicular dendritic cells to Ab formation. Specific Aim 3: Examine host predictors of PF4/heparin seroconversion. Complement-coated antigen can be detected on B-cells in some, but not all, patients receiving heparin therapy. Using a novel C3 capture immunoassay, we also show significant donor to donor variation in healthy donor plasma incubated with a fixed dose of PF4/heparin. Based on these observations, we will examine host susceptibility to anti- PF4/heparin seroconversions by characterizing the complement proteome and using antigen-positive B-cells as a marker for seroconversions in heparinized patients. By defining the cellular pathways that initiate formation of PF4/heparin Abs, we hope to uncover mechanisms relevant to the immunogenicity of other auto- or exogenous antigens.

抽象的 肝素诱导的血小板减少症（HIT）是一种威胁生命的免疫介导的血栓性疾病 PF4/肝素复合物的抗体。免疫反应很普遍，但对其的理解很少 在最后的资金期间，我们做出了与周围早期事件有关的基本观察 主持人与PF4/肝素抗原综合体相遇。具体来说，我们显示：1）优先结合 与其他白细胞或血小板相比，PF4/肝素至循环B细胞，2）肝素依赖性 在接受肝素的患者中，PF4/肝素与B细胞结合，3）PF4/肝素抗原的完成固定， 4）补体介导的PF4/肝素与接受肝素的患者的循环B细胞结合，5）结合 通过补体受体2（CR2/ CD21）对B细胞的补体抗原。在以下目标中，我们将 检验以下假设，即PF4/肝素复合物的完成和抗原沉积在B细胞上 通过CD21对于开发HIT自身抗体至关重要。特定目标1：完成机制 PF4/肝素复合物激活。在初步数据中，我们表明甘露糖结合讲座和ficolin-2 结合PF4/肝素复合物。基于这些发现，我们将测试PF4/肝素复合物的假设 通过Leverin途径激活补体。我们将定义PF4/肝素 - 乳蛋白的结构基础 相互作用，讲座与PF4/肝素复合物的研究功能相互作用，并检查 补充抑制作用。特定目标2：CD21参与的细胞后果 PF4/肝素和完成。补体涂层抗原与CD21的结合增强体液免疫史 在103至104倍上。我们假设补体涂层的多价PF4/肝素与CD21结合 复杂促进抗原特异性B细胞的募集和信号传导。我们将检查下游 同源和非同名B细胞的信号传导，激活和增殖，在小鼠中进行体内研究 固定B细胞接收器并表征表达CD21的卵泡树突状细胞对AB的贡献 形成。特定目标3：检查PF4/肝素血清转化的宿主预测因子。补充涂层 在某些但不是全部接受肝素治疗的患者中，可以在B细胞上检测到抗原。使用新颖的C3 捕获免疫测定法，我们还向健康供体血浆中的供体变异显示了重要的供体 固定剂量的PF4/肝素。基于这些观察结果，我们将检查宿主对抗抗的敏感性 PF4/肝素血清转化通过表征补体蛋白质组和使用抗原阳性B细胞 作为肝素化患者血清转化的标记。通过定义启动的细胞途径 PF4/肝素ABS的形成，我们希望发现与其他自动的免疫原性有关的机制 或外源抗原。

项目成果

Combination of aptamer and drug for reversible anticoagulation in cardiopulmonary bypass.

• DOI: 10.1038/nbt.4153
• 发表时间: 2018-08
• 期刊: Nature biotechnology
• 影响因子: 46.9
• 作者: Gunaratne R;Kumar S;Frederiksen JW;Stayrook S;Lohrmann JL;Perry K;Bompiani KM;Chabata CV;Thalji NK;Ho MD;Arepally G;Camire RM;Krishnaswamy S;Sullenger BA
• 通讯作者: Sullenger BA

Molecular and cellular pathogenesis of heparin-induced thrombocytopenia (HIT).

肝素诱导的血小板减少症（HIT）的分子和细胞发病机制。

• DOI: 10.1016/j.autrev.2018.05.003
• 发表时间: 2018
• 期刊: Autoimmunity reviews
• 影响因子: 13.6
• 作者: Rauova,Lubica;Arepally,Gowthami;Poncz,Mortimer;Cines,DouglasB
• 通讯作者: Cines,DouglasB

Vaccine-induced immune thrombotic thrombocytopenia: what we know and do not know.

• DOI: 10.1182/blood.2021012152
• 发表时间: 2021-07-29
• 期刊: Blood
• 影响因子: 20.3
• 作者: Arepally GM;Ortel TL
• 通讯作者: Ortel TL

Neutrophil functional heterogeneity is a fixed phenotype and is associated with distinct gene expression profiles.

• DOI: 10.1002/jlb.4a0322-164r
• 发表时间: 2022-12
• 期刊: JOURNAL OF LEUKOCYTE BIOLOGY
• 影响因子: 5.5
• 作者: Maskarinec, Stacey A.;McKelvy, Margaret;Boyle, Kimberly;Hotchkiss, Halie;Duarte, Madelaine E.;Addison, Bechtler;Amato, Nicholas;Khandelwal, Sanjay;Arepally, Gowthami M.;Lee, Grace M.
• 通讯作者: Lee, Grace M.

Heparin-Induced Thrombocytopenia: A Focus on Thrombosis.

• DOI: 10.1161/atvbaha.120.315445
• 发表时间: 2021-01
• 期刊: Arteriosclerosis, thrombosis, and vascular biology
• 作者: Arepally GM;Padmanabhan A
• 通讯作者: Padmanabhan A