Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53711, USA.
Space Data Science and Systems, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Sci Transl Med. 2022 Aug 10;14(657):eabm4908. doi: 10.1126/scitranslmed.abm4908.
The SARS-CoV-2 B.1.621 (Mu) variant emerged in January 2021 and was categorized as a variant of interest by the World Health Organization in August 2021. This designation prompted us to study the sensitivity of this variant to antibody neutralization. In a live virus neutralization assay with serum samples from individuals vaccinated with the Pfizer/BioNTech or Moderna mRNA vaccines, we measured neutralization antibody titers against B.1.621, an early isolate (spike 614D), and a variant of concern (B.1.351, Beta variant). We observed reduced neutralizing antibody titers against the B.1.621 variant (3.4- to 7-fold reduction, depending on the serum sample and time after the second vaccination) compared to the early isolate and a similar reduction when compared to B.1.351. Likewise, convalescent serum from hamsters previously infected with an early isolate neutralized B.1.621 to a lower degree. Despite this antibody titer reduction, hamsters could not be efficiently rechallenged with the B.1.621 variant, suggesting that the immune response to the first infection is adequate to provide protection against a subsequent infection with the B.1.621 variant.
2021 年 1 月出现的 SARS-CoV-2 B.1.621（Mu）变体，于 2021 年 8 月被世界卫生组织归类为值得关注的变体。这一指定促使我们研究该变体对抗体中和的敏感性。在一项使用辉瑞/生物科技或 Moderna mRNA 疫苗接种个体的血清样本进行的活病毒中和测定中，我们测量了针对 B.1.621、早期分离株（刺突 614D）和一种关注变体（B.1.351，Beta 变体）的中和抗体滴度。与早期分离株相比，我们观察到针对 B.1.621 变体的中和抗体滴度降低（取决于血清样本和第二次接种后的时间，降低 3.4-7 倍），与 B.1.351 相比也有类似的降低。同样，先前感染过早期分离株的仓鼠恢复期血清对 B.1.621 的中和能力也较低。尽管抗体滴度降低，但 B.1.621 变体不能有效地再次感染仓鼠，这表明对初次感染的免疫反应足以提供对随后感染 B.1.621 变体的保护。
