SARS-CoV-2: Pathogenesis and Countermeasure Development

自2020年2月以来，我们一直主要从事COVID项目。我们已经建立了叙利亚仓鼠疾病模型，用于发病机制研究和对策开发(Rosenke等人，手稿正在准备中)。我们已经建立了一条体外药物筛选管道，该管道将使用叙利亚仓鼠模型将有希望的候选药物输送到体内测试(Jarvis等人，Antivir Ther 2020；Rosenke等人，J Antim微生物Chemtherap，提交)。这些研究正在进行中。我们进一步评估了羟基氯喹(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，标准的人类疟疾HCQ预防和治疗没有显著改善临床结果，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，无论是标准的人类疟疾剂量还是大剂量的HCQ，都对临床疾病或叙利亚仓鼠疾病模型中的SARS-CoV-2动力学(复制/脱落)没有任何有利影响。这两个临床前动物模型的结果可能有助于指导临床使用氢氯喹酮预防/治疗新冠肺炎。最后，我们迅速开发出了一种稳定的、高免疫原性的候选疫苗，它由一种RNA复制子组成，该复制子由一种新型的脂质无机纳米颗粒(LION)配制而成，旨在增强疫苗的稳定性、递送能力和免疫原性。我们已经证明，肌肉注射Lion/epRNA-CoV2S可以在小鼠中诱导出强大的抗SARS-CoV-2刺突蛋白IgG抗体亚型，表明有1型T辅助反应和强大的T细胞反应。重要的是，在非人类灵长类动物中仅使用PRIME可诱导抗体反应，有效中和SARS-CoV-2以及指示1型T辅助反应的T细胞反应。这些数据支持进一步开发Lion/epRNA-CoV2S作为预防SARS-CoV-2感染的候选疫苗(Erasmus等人，Sci Transl Med 2020)。 在2月份对马里的一次定期访问期间，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.