Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of Coronavirus Disease 2019 (COVID-19), has caused a global pandemic, and safe, effective vaccines are urgently needed¹. Strong, Th1-skewed T cell responses can drive protective humoral and cell-mediated immune responses² and might reduce the potential for disease enhancement³. Cytotoxic T cells clear virus-infected host cells and contribute to control of infection⁴. Studies of patients infected with SARS-CoV-2 have suggested a protective role for both humoral and cell-mediated immune responses in recovery from COVID-19 (refs. ^5,6). ChAdOx1 nCoV-19 (AZD1222) is a candidate SARS-CoV-2 vaccine comprising a replication-deficient simian adenovirus expressing full-length SARS-CoV-2 spike protein. We recently reported preliminary safety and immunogenicity data from a phase 1/2 trial of the ChAdOx1 nCoV-19 vaccine (NCT04400838)⁷ given as either a one- or two-dose regimen. The vaccine was tolerated, with induction of neutralizing antibodies and antigen-specific T cells against the SARS-CoV-2 spike protein. Here we describe, in detail, exploratory analyses of the immune responses in adults, aged 18–55 years, up to 8 weeks after vaccination with a single dose of ChAdOx1 nCoV-19 in this trial, demonstrating an induction of a Th1-biased response characterized by interferon-γ and tumor necrosis factor-α cytokine secretion by CD4⁺ T cells and antibody production predominantly of IgG1 and IgG3 subclasses. CD8⁺ T cells, of monofunctional, polyfunctional and cytotoxic phenotypes, were also induced. Taken together, these results suggest a favorable immune profile induced by ChAdOx1 nCoV-19 vaccine, supporting the progression of this vaccine candidate to ongoing phase 2/3 trials to assess vaccine efficacy.

严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 是 2019 年冠状病毒病 (COVID-19) 的病原体，已引起全球大流行，迫切需要安全、有效的疫苗¹ 。强烈的、Th1 倾向的 T 细胞反应可以驱动保护性体液和细胞介导的免疫反应² ，并可能降低疾病增强的可能性³ 。细胞毒性 T 细胞清除病毒感染的宿主细胞并有助于控制感染⁴ 。对感染 SARS-CoV-2 的患者的研究表明，体液和细胞介导的免疫反应在 COVID-19 康复过程中具有保护作用（参考文献^5,6 ）。 ChAdOx1 nCoV-19 (AZD1222) 是一种候选 SARS-CoV-2 疫苗，包含表达全长 SARS-CoV-2 刺突蛋白的复制缺陷型猿腺病毒。我们最近报告了 ChAdOx1 nCoV-19 疫苗 (NCT04400838) ⁷的 1/2 期试验的初步安全性和免疫原性数据，该疫苗以一剂或两剂方案给药。该疫苗具有耐受性，可诱导针对 SARS-CoV-2 刺突蛋白的中和抗体和抗原特异性 T 细胞。在这里，我们详细描述了本试验中 18-55 岁成人在接种单剂 ChAdOx1 nCoV-19 疫苗后长达 8 周的免疫反应的探索性分析，证明了 Th1 偏向反应的诱导其特征是 CD4 ⁺ T 细胞分泌干扰素-γ 和肿瘤坏死因子-α 细胞因子，以及主要产生 IgG1 和 IgG3 亚类的抗体。还诱导了单功能、多功能和细胞毒性表型的CD8 ⁺ T细胞。 总而言之，这些结果表明 ChAdOx1 nCoV-19 疫苗诱导了良好的免疫特征，支持该候选疫苗进入正在进行的 2/3 期试验以评估疫苗功效。