SARS-CoV-2: Pathogenesis and Countermeasure Development

自2020年2月起，我们主要致力于COVID项目。我们已经建立了叙利亚仓鼠病模型用于发病机理研究和对策开发（Rosenke et al.，手稿正在准备中）。我们已经建立了体外药物筛选管道，其将使用叙利亚仓鼠模型将有希望的候选物送入体内测试（Jarvis等人，Antivir Ther 2020; Rosenke等人，J Antimicrobial Chemotherap，已提交）。这些研究正在进行中。我们进一步评估了羟氯喹（HCQ）在两种动物疾病模型中的预防/治疗效果。在恒河猴疾病模型中，标准的人疟疾HCQ预防和治疗既没有显著的临床效果，也没有减少SARS-CoV-2在上呼吸道和下呼吸道的复制/脱落。同样，当用于预防或治疗时，标准人疟疾剂量或高剂量HCQ对叙利亚仓鼠疾病模型中的临床疾病或SARS-CoV-2动力学（复制/脱落）均无任何有益作用。这两种临床前动物模型的结果可能有助于指导HCQ用于预防/治疗COVID-19的临床使用。最后，我们快速开发了repRNA-CoV 2S，这是一种稳定且高度免疫原性的候选疫苗，由RNA复制子组成，该复制子与新型脂质无机纳米颗粒（LION）一起配制，旨在增强疫苗稳定性，递送和免疫原性。我们已经表明，肌内注射LION/repRNA-CoV 2S在小鼠中引发了强烈的抗SARS-CoV-2刺突蛋白IgG抗体同种型，表明1型T辅助应答以及有效的T细胞应答。重要的是，在非人灵长类动物中仅引发的给药引起了有效中和SARS-CoV-2的抗体应答以及指示1型T辅助应答的T细胞应答。这些数据支持进一步开发LION/repRNA-CoV 2S作为预防SARS-CoV-2感染的疫苗候选物（Erasmus等，Sci Transl Med 2020）。 今年2月，在我们对马里的ICER站点进行定期访问期间，我们开发并建立了针对新出现的SARS-CoV-2的诊断测试。当时马里没有任何新冠肺炎病例，这种情况已经发生了巨大变化。ICER站点（G点）现在是马里4个国家COVID检测诊断中心之一。

Since February 2020 we have been mainly working on COVID projects. We have established the Syrian hamster disease model for pathogenesis studies and countermeasure development (Rosenke et al., manuscript in preparation). We have established an in vitro drug screening pipeline that will feed promising candidates into in vivo testing using the Syrian hamster model (Jarvis et al., Antivir Ther 2020; Rosenke et al., J Antimicrobial Chemotherap, submitted). These studies are ongoing. We further assessed the prophylactic/therapeutic efficacy of hydroxychloroquine (HCQ) in two animal disease models. The standard human malaria HCQ prophylaxis and treatment did not significantly benefit clinical outcome nor reduce SARS-CoV-2 replication/shedding in the upper and lower respiratory tract in the rhesus macaque disease model. Similarly, when used for prophylaxis or treatment neither the standard human malaria dose nor a high dose of HCQ had any beneficial effect on clinical disease or SARS-CoV-2 kinetics (replication/shedding) in the Syrian hamster disease model. Results from these two preclinical animal models may prove helpful in guiding clinical use of HCQ for prophylaxis/treatment of COVID-19. Finally, we have rapidly developed repRNA-CoV2S, a stable and highly immunogenic vaccine candidate comprised of an RNA replicon formulated with a novel Lipid InOrganic Nanoparticle (LION) designed to enhance vaccine stability, delivery, and immunogenicity. We have shown that intramuscular injection of LION/repRNA-CoV2S elicited robust anti-SARS-CoV-2 spike protein IgG antibody isotypes indicative of a Type 1 T helper response as well as potent T cell responses in mice. Importantly, a prime-only administration in nonhuman primates elicited antibody responses that potently neutralized SARS-CoV-2 as well as T cell responses indicative of a Type 1 T helper response. These data support further development of LION/repRNA-CoV2S as a vaccine candidate for prophylactic protection from SARS-CoV-2 infection (Erasmus et al., Sci Transl Med 2020). During a regular visit in Mali, our ICER site, in February, we developed and established diagnostic testing for the emerging SARS-CoV-2. At that time Mali did not have any COVID cases, a situation that has changed dramatically. The ICER site (Point G) is now one of 4 national diagnostic centers for COVID testing in Mali.