Recent studies have reported protective efficacy of both natural immunity1 and vaccine-induced immunity2-7 against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) challenge in rhesus macaques. However, the importance of humoral and cellular immunity for protection against SARS-CoV-2 infection remains to be determined. Here we show that adoptive transfer of purified IgG from convalescent macaques protects naïve recipient rhesus macaques against SARS-CoV-2 challenge in a dose dependent fashion. Depletion of CD8+ T cells in convalescent animals partially abrogated the protective efficacy of natural immunity against SARS-CoV-2 re-challenge, suggesting the importance of cellular immunity in the context of waning or subprotective antibody titers. These data demonstrate that relatively low antibody titers are sufficient for protection against SARS-CoV-2 in rhesus macaques, and that cellular immune responses may also contribute to protection if antibody responses are suboptimal. We also show that higher antibody titers are required for therapy of SARS-CoV-2 infection in macaques. These findings have important implications for the development of SARS-CoV-2 vaccines and immune-based therapeutics.

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恒河猴抗 SARS-CoV-2 的相关性

最近的研究报告了自然免疫 1 和疫苗诱导的免疫 2-7 对恒河猴严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 攻击的保护功效。然而，体液免疫和细胞免疫对于防止 SARS-CoV-2 感染的重要性仍有待确定。在这里，我们表明从恢复期的猕猴中过继转移纯化的 IgG 以剂量依赖性方式保护幼稚的受体恒河猴免受 SARS-CoV-2 攻击。恢复期动物中 CD8+ T 细胞的消耗部分消除了自然免疫对 SARS-CoV-2 再攻击的保护功效，这表明细胞免疫在抗体滴度减弱或亚保护性的情况下的重要性。这些数据表明，相对较低的抗体滴度足以保护恒河猴免受 SARS-CoV-2 的侵害，如果抗体反应不理想，细胞免疫反应也可能有助于保护。我们还表明，治疗猕猴 SARS-CoV-2 感染需要更高的抗体滴度。这些发现对 SARS-CoV-2 疫苗和免疫疗法的开发具有重要意义。