Discovery & characterization of human monoclonal antibodies targeting multiple arthritogenic alphaviruses

项目摘要 甲病毒是有包膜的正义单链RNA病毒，其包括几种甲病毒。 重要的人类病原体致关节炎甲病毒是全球分布的蚊媒病毒 引起人类风湿性疾病的病毒，包括基孔肯雅病毒（CHIKV）和马亚罗病毒（MAYV）。 症状感染的特点是发烧，皮疹，肌痛，以及急性和慢性多关节痛 感染后可持续数月至数年更严重的甲病毒病表现- 包括出血、脑病和死亡。这些病毒引起地方性流行病 疾病以及大规模的、零星的流行病。目前，没有批准的疫苗或抗病毒药物 用于预防或治疗甲病毒感染的新疗法的开发;因此， 靶向一种或多种致关节炎甲病毒的策略受到极大关注。 已经描述了许多有效中和CHIKV的单克隆抗体（mAb），但是 目前报道的唯一广泛中和的甲病毒单克隆抗体是鼠的。因此， 所述人抗体应答在甲病毒感染后产生广泛中和的mAb，并且 这种mAb可能靶向的表位仍然未知。为解决这一问题，本提案旨在扩大 我们通过系统地研究交叉， 来自CHIKV感染患者的反应性抗体。为此，我们使用单B细胞分选， 从处于恢复期的CHIKV患者中分离大量MAYV反应性mAb。我们将研究 这些mAb针对相关致关节炎甲病毒的反应性和中和特征（Aim 1）。我们 然后将通过生物化学方法确定中和的要求（目标2），并阐明 mAb抑制（目的3）。这些研究将有助于我们从根本上理解适应性 免疫系统对抗致关节炎甲病毒的感染，并可能有助于开发新的mAb- 治疗和疫苗。

Project Summary Alphaviruses are enveloped, positive sense single-stranded RNA viruses, which include several important human pathogens. Arthritogenic alphaviruses are globally distributed, mosquito-transmitted viruses that cause human rheumatic disease and include chikungunya virus (CHIKV) and Mayaro virus (MAYV). Symptomatic infection is characterized by fever, rash, myalgia, as well as both acute and chronic polyarthralgia that can persist for months to years after infection. More severe manifestations of alphaviral disease – including hemorrhage, encephalopathy and mortality – have been reported. These viruses cause endemic disease as well as large, sporadic epidemics worldwide. Currently, there are no approved vaccines or anti-viral therapies for the prevention or treatment of alphavirus infection; therefore, the development of new therapeutic strategies targeting one or multiple arthritogenic alphaviruses is of substantial interest. A number of potently neutralizing CHIKV monoclonal antibodies (mAbs) have been described, but currently the only broadly neutralizing alphavirus mAbs that have been reported are murine. Thus, the extent to which the human antibody response elicits broadly-neutralizing mAbs following alphavirus infection, and which epitope(s) such mAbs may target, remains unknown. To address this question, this proposal seeks to expand our knowledge of the neutralizing antibody response to alphaviruses by systematically investigating cross- reactive antibodies from CHIKV-infected patients. Towards this end, we have used single B cell sorting to isolate a large panel of MAYV-reactive mAbs from CHIKV patients in the convalescent phase. We will study the reactivity and neutralization profiles of these mAbs against related arthitogenic alphaviruses (Aim 1). We will then biochemically determine the requirements of neutralization (Aim 2) and elucidate the mechanism of mAb inhibition (Aim 3). These studies will contribute to our fundamental understanding of how the adaptive immune system combats infection by arthritogenic alphaviruses and may aid the development of novel mAb- based treatments and vaccines.