Department of Pathology, Medical College of Georgia, Augusta University, Augusta, GA, United States.
Department of Neurosurgery, Augusta University, Augusta, GA, United States.
Front Immunol. 2021 May 11;12:660019. doi: 10.3389/fimmu.2021.660019. eCollection 2021.
SARS-CoV-2 is the cause of a recent pandemic that has led to more than 3 million deaths worldwide. Most individuals are asymptomatic or display mild symptoms, which raises an inherent question as to how does the immune response differs from patients manifesting severe disease? During the initial phase of infection, dysregulated effector immune cells such as neutrophils, macrophages, monocytes, megakaryocytes, basophils, eosinophils, erythroid progenitor cells, and Th17 cells can alter the trajectory of an infected patient to severe disease. On the other hand, properly functioning CD4+, CD8+ cells, NK cells, and DCs reduce the disease severity. Detailed understanding of the immune response of convalescent individuals transitioning from the effector phase to the immunogenic memory phase can provide vital clues to understanding essential variables to assess vaccine-induced protection. Although neutralizing antibodies can wane over time, long-lasting B and T memory cells can persist in recovered individuals. The natural immunological memory captures the diverse repertoire of SARS-CoV-2 epitopes after natural infection whereas, currently approved vaccines are based on a single epitope, spike protein. It is essential to understand the nature of the immune response to natural infection to better identify 'correlates of protection' against this disease. This article discusses recent findings regarding immune response against natural infection to SARS-CoV-2 and the nature of immunogenic memory. More precise knowledge of the acute phase of immune response and its transition to immunological memory will contribute to the future design of vaccines and the identification of variables essential to maintain immune protection across diverse populations.
SARS-CoV-2 是导致全球超过 300 万人死亡的近期大流行的病原体。大多数个体无症状或表现出轻微症状，这就提出了一个内在问题，即免疫反应如何与表现出严重疾病的患者不同？在感染的初始阶段，失调的效应免疫细胞，如中性粒细胞、巨噬细胞、单核细胞、巨核细胞、嗜碱性粒细胞、嗜酸性粒细胞、红细胞祖细胞和 Th17 细胞，可以改变感染患者的病程，使其发展为严重疾病。另一方面，正常功能的 CD4+、CD8+细胞、NK 细胞和 DC 可以降低疾病的严重程度。详细了解从效应期过渡到免疫记忆期的恢复期个体的免疫反应，可以为理解评估疫苗诱导保护所需的基本变量提供重要线索。尽管中和抗体可能随时间减弱，但在康复个体中，B 细胞和 T 细胞记忆细胞可以长期存在。自然免疫记忆在自然感染后捕获 SARS-CoV-2 表位的多样化谱，而目前批准的疫苗基于单一表位，即刺突蛋白。了解自然感染的免疫反应的性质对于更好地确定针对这种疾病的“保护相关因素”至关重要。本文讨论了关于针对 SARS-CoV-2 的自然感染的免疫反应和免疫记忆性质的最新发现。更精确地了解免疫反应的急性期及其向免疫记忆的转变，将有助于未来疫苗的设计和确定维持不同人群免疫保护所需的变量。
