BNT162b2, a nucleoside-modified mRNA formulated in lipid nanoparticles that encodes the SARS-CoV-2 spike glycoprotein (S) stabilized in its prefusion conformation, has demonstrated 95% efficacy in preventing COVID-19¹. Here we extend a previous phase-I/II trial report² by presenting data on the immune response induced by BNT162b2 prime–boost vaccination from an additional phase-I/II trial in healthy adults (18–55 years old). BNT162b2 elicited strong antibody responses: at one week after the boost, SARS-CoV-2 serum geometric mean 50% neutralizing titres were up to 3.3-fold above those observed in samples from individuals who had recovered from COVID-19. Sera elicited by BNT162b2 neutralized 22 pseudoviruses bearing the S of different SARS-CoV-2 variants. Most participants had a strong response of IFNγ⁺ or IL-2⁺ CD8⁺ and CD4⁺ T helper type 1 cells, which was detectable throughout the full observation period of nine weeks following the boost. Using peptide–MHC multimer technology, we identified several BNT162b2-induced epitopes that were presented by frequent MHC alleles and conserved in mutant strains. One week after the boost, epitope-specific CD8⁺ T cells of the early-differentiated effector-memory phenotype comprised 0.02–2.92% of total circulating CD8⁺ T cells and were detectable (0.01–0.28%) eight weeks later. In summary, BNT162b2 elicits an adaptive humoral and poly-specific cellular immune response against epitopes that are conserved in a broad range of variants, at well-tolerated doses.

BNT162b2 是一种在脂质纳米颗粒中配制的核苷修饰 mRNA，可编码稳定在其融合前构象中的 SARS-CoV-2 刺突糖蛋白 (S)，已显示出 95% 的预防 COVID-19^功效。在这里，我们扩展了之前的 I/II 期试验报告²通过在健康成人（18-55 岁）中进行的另一项 I/II 期试验中提供有关 BNT162b2 初免疫苗诱导的免疫反应的数据。BNT162b2 引发了强烈的抗体反应：在加强后一周，SARS-CoV-2 血清几何平均 50% 中和滴度比从 COVID-19 康复者的样本中观察到的滴度高出 3.3 倍。BNT162b2 引发的血清中和了 22 种带有不同 SARS-CoV-2 变体 S 的假病毒。大多数参与者对 IFNγ ⁺或 IL-2 ⁺ CD8 ⁺和 CD4 ^{+有强烈反应}T 辅助 1 型细胞，在加强后 9 周的整个观察期内均可检测到。使用肽-MHC 多聚体技术，我们鉴定了几个由常见的 MHC 等位基因呈递并在突变菌株中保守的 BNT162b2 诱导的表位。加强后一周，早期分化效应记忆表型的表位特异性 CD8 ⁺ T 细胞占总循环 CD8 ⁺ T 细胞的 0.02-2.92%，八周后可检测到 (0.01-0.28%)。总之，在耐受良好的剂量下，BNT162b2 引发针对在广泛变体中保守的表位的适应性体液和多特异性细胞免疫反应。