Antibody-based therapeutic strategy for New World mammarenavirus hemorrhagic fever

科学摘要 五种新世界哺乳动物病毒(NWM)可引起危及生命的病毒性出血热。NWM 向人类传播最常见的途径是吸入雾化病毒颗粒或直接 接触含病毒的啮齿动物排泄物或分泌物。致病性NWM被认为是优先病原体 联邦和国际公共卫生机构，因为它们构成了重大的公共卫生风险和威胁 为国家安全干杯。因此，迫切需要开发新的策略来治疗NWM感染。一个 致病性NWMS的特征是能够通过人转铁蛋白受体1进入细胞 (TfR1)，也称为CD71。NWM与TfR1的结合是通过其包膜的相互作用实现的 糖蛋白GP1亚基连接到TfR1的顶端区域，位于转铁蛋白(Tf)结合部位之外，它 提出了一种广泛有效的药物开发的靶点，该药物可以破坏病毒GP1与TfR1的连接 而不会干扰细胞对铁的吸收。我们已经开发出一种鼠/人嵌合抗体(Ab)， Ch128.1/IgG1，靶向人TfR1的顶端结构域，有效地与致病性NWM竞争 在我们开发的致死性JUNV疾病模型中提供了保护作用 表达人TfR1的转基因小鼠(huTfR1Tg小鼠)。与抗体的竞争性质一致 作用机制，使用FcgR和C1q受损的ch128.1/IgG1突变体保护效果更好 结合，导致抗体Fc受体效应器功能缺失(Fc沉默；Fc/S)。与人类数据一致，我们 还发现，血液中干扰素-a水平的升高在严重的NWM的发病机制中起着重要作用。 感染。我们最近还开发了ch128.1/IgG1(hu128.1)的人源化版本，它不仅 增加人类抗体可变区的含量供人类使用，但也保留嵌合抗体 具有优异的性能和优异的热稳定性，使其成为更好的治疗候选药物。我们假设 TfR1可作为中和NWM感染的有效靶点，而不仅仅是利用抗TfR1抗体 Ch128.1/IgG1Fc/S，也使用新的hu128.1 Fc/S作为单体和聚合物类IgG1IgG1. 阿布。我们还假设，使用针对干扰素-a/b受体IFNAR-1(MaR1-5A3)的拮抗剂 AB)将有效预防严重的NWM疾病，作为单一疗法使用或与抗TfR1联合使用 腹肌。为了检验我们的假设，我们有四个具体目标。目的1：确定ch128.1 Fc/S和MaR1- 5a3作为单一疗法或联合疗法抑制/消除huTfR1Tg小鼠NWM感染；目的2： 开发hu128.1 Fc/S和类IgM型hu128.1 IgG1Fc/S作为治疗NWM感染的新抗体； 目的3：确定hu128.1 Fc/S和类IgM型hu128.1 IgG1Fc/S在细胞培养和huTfR1中的抗病毒活性 Tg小鼠NWM感染模型；以及目标4：确定一种选定的非人类抗TfR1抗体的特性 灵长类(NHP)。本项目将为新型抗TfR1抗体和抗TfR1抗体的应用奠定科学基础。 IFNAR-1抗体用于治疗NWM感染，并导致更好地了解相关疾病。

SCIENTIFIC ABSTRACT Five New World mammarenaviruses (NWMs) cause life-threatening viral hemorrhagic fever. NWM transmission to humans most commonly occurs through inhalation of aerosolized viral particles or direct contact with virus-containing rodent excreta or secreta. Pathogenic NWMs are considered priority pathogens by federal and international public health agencies because they pose a significant public health risk and threat to national security. Thus, there is an urgent need to develop new strategies to treat NWM infection. A distinguishing feature of the pathogenic NWMs is the ability to enter cells through human transferrin receptor 1 (TfR1), also known as CD71. Binding of NWMs to TfR1 occurs through the interaction of their envelope glycoprotein GP1 subunit to the apical domain of TfR1, outside of the transferrin (Tf) binding site, which presents a target for the development of broadly active therapeutics that disrupt viral GP1 attachment to TfR1 without interfering with cellular uptake of iron. We have developed a mouse/human chimeric antibody (Ab), ch128.1/IgG1, targeting the apical domain of human TfR1 that effectively competes with pathogenic NWM cellular entry in vitro and provides protection in a model of lethal JUNV disease that we developed using transgenic mice expressing human TfR1 (huTfR1 Tg mice). Consistent with the competitive nature of the Ab mechanism of action, protection was superior using a ch128.1/IgG1 mutant with impaired FcgR and C1q binding, resulting in lack of Ab Fc receptor effector functions (Fc silent; Fc/s). Consistent with human data, we also found that increased interferon-a (IFN-a) blood levels are important in the pathogenesis of severe NWM infection. We have also recently developed a humanized version of ch128.1/IgG1 (hu128.1), which not only increases the human content of the Ab variable regions for human use but also retains the chimeric Ab properties and exhibits superior thermal stability, making it a better therapeutic candidate. We hypothesize that TfR1 can be used as an effective target to neutralize NWM infection, not only using the anti-TfR1 Ab ch128.1/IgG1 Fc/s but also using a new hu128.1 Fc/s as monomeric IgG1 and also as polymeric IgM-like IgG1 Ab. We also hypothesize that the use of an antagonistic Ab specific for IFN-a/b receptor IFNAR-1 (MAR1-5A3 Ab) would be effective in preventing severe NWM disease, used as a monotherapy or combined with anti-TfR1 Abs. To test our hypotheses, we have four Specific Aims. Aim 1: Define the ability of ch128.1 Fc/s and MAR1- 5A3 as monotherapy or combination therapy to inhibit/eliminate NWM infection in huTfR1 Tg mice; Aim 2: Develop a hu128.1 Fc/s and an IgM-like hu128.1 IgG1 Fc/s as novel therapeutic Abs against NWM infection; Aim 3: Define the antiviral activity of hu128.1 Fc/s and IgM-like hu128.1 IgG1 Fc/s in cell culture and huTfR1 Tg mice NWM infection models; and Aim 4: Define the properties of a selected anti-TfR1 Ab in non-human primates (NHPs). This project will develop the scientific basis for the use of novel anti-TfR1 and anti- IFNAR-1 Abs to treat NWM infection and result in a better understanding of the associated disease.