Engineering Protein Antigens and their Presentation from Multivalent Scaffolds

这项拟议工作的目标是开发一种对第一群人具有广泛保护作用的疫苗。 甲型流感病毒-包括1918年、1957-1958年和2009年大流行病毒以及禽类病毒的一组病毒 流感“令人关注的病毒”--通过激发针对高度感染的 血凝素(HA)的膜-近端茎段保守。该项目将检验这一假设 屏蔽HA的可变头结构域，将免疫应答重新聚焦于高度 通过控制HA的取向和多价递呈，保守的茎结构域将提供广泛的， 对1组甲型流感病毒的持久和强大的保护。流感代表着一种严重的全球健康 问题，季节性流感病毒感染给健康和经济造成重大负担，以及 由新型流感病毒引起的大流行代表着更严重的威胁。领有执照的疫苗 诱导主要针对HA头部区域的免疫反应，HA的头部区域在 序列。因此，对流感疫苗接种的免疫反应是狭隘的和特定毒株的，并将 对潜在的大流行性流感病毒几乎没有提供保护。同时“广泛中和”抗体 以HA高度保守的茎结构域为靶点在预防和治疗方面具有保护作用 流感病毒在体内的挑战，这种抗体在自然感染或经许可的情况下不能有效地激发 流感疫苗。HA茎段的免疫优势可能源于其近端的膜 定位，B细胞受体与保守的茎表位的相互作用被空间位阻挡 病毒粒子上密密麻麻地堆积着糖蛋白。事实上，我们最近已经证明，调整 定向HA以提高茎表位的可及性导致增强保护性茎定向 免疫反应。此外，我们还展示了一种方法(束缚抗原抑制)，用于 抑制针对HA头部区域的免疫反应，并将免疫反应重新聚焦于所需的 表位(如茎)。我们还设计了能够引起强大的保护性抗体反应的疫苗。 通过多价展示病毒样颗粒来对抗包括HA在内的各种抗原。第一 拟议工作的目的是设计和测试新的HA抗原设计，以提供增强的茎- 定向免疫反应。我们将屏蔽HA的头部结构域以抑制其免疫原性并将调整 头罩HA的取向以增加茎结构域的可达性并增强其 免疫原性。我们还将调查是否有能力通过使用 经过改造的HA抗原，融合了来自不同病毒亚型的茎域。第二个目标是 表征接种疫苗在小鼠体内引起的抗茎反应的广度和寿命。第三 目的是研究未接种和预免疫的男性和女性的免疫原性和疫苗效力。 雪貂。

The objective of the proposed work is to develop a vaccine that provides broad protection against group 1 influenza A viruses – a group that includes the 1918, 1957-1958, and 2009 pandemic viruses, as well as avian influenza “viruses of concern” – by eliciting a robust and durable immune response targeting the highly conserved membrane-proximal stalk domain of hemagglutinin (HA). The project will test the hypothesis that the combination of shielding the variable head domain of HA, refocusing the immune response to the highly conserved stalk domain by controlling the orientation of HA, and multivalent presentation, will provide broad, durable, and robust protection against group 1 influenza A viruses. Influenza represents a serious global health problem, with seasonal influenza virus infections imposing significant health and economic burdens, and pandemics caused by novel influenza viruses representing an even more serious threat. Licensed vaccines induce an immune response that primarily targets the head domain of HA, which is highly variable in sequence. As a result, the immune response to influenza vaccination is narrow and strain-specific and would provide little protection against potential pandemic influenza viruses. While “broadly neutralizing” antibodies targeting the highly conserved stalk domain of HA are prophylactically and therapeutically protective against influenza virus challenges in vivo, such antibodies are not elicited effectively in natural infections or by licensed influenza vaccines. The immunosubdominance of the HA stalk domain may result from its membrane-proximal location, with interactions of B-cell receptors with conserved stalk epitopes being blocked by steric hindrance on virions which are densely packed with glycoproteins. Indeed, we have recently shown that tuning the orientation of HA to enhance the accessibility of stalk epitopes results in an enhanced protective stalk-directed immune response. Furthermore, we have demonstrated an approach (tethered antigenic suppression) for suppressing the immune response to the head domain of HA and refocusing the immune response on desired epitopes (such as the stalk). We have also designed vaccines that elicit a robust protective antibody response against a variety of antigens, including HA, by displaying them multivalently from virus-like particles. The first aim of the proposed work is to engineer and test novel HA antigen designs to provide an enhanced stalk- directed immune response. We will shield the head domain of HA to suppress its immunogenicity and will tune the orientation of the head-shielded HA to increase the accessibility of the stalk domain and enhance its immunogenicity. We will also investigate the ability to further increase the breadth of protection by using engineered HA antigens that incorporate stalk domains from different viral subtypes. The second aim is to characterize the breadth and the longevity of the anti-stalk response induced by vaccination in mice. The third aim is to characterize immunogenicity and vaccine efficacy in naïve and pre-immunized, male and female ferrets.