Characterization of SARS-CoV-2 Variants B.1.617.1 (Kappa), B.1.617.2 (Delta), and B.1.618 by Cell Entry and Immune Evasion
Wenlin Ren, Xiaohui Ju, Mingli Gong, Jun Lan, Yanying Yu, Quanxin Long, Devin Kenney, Aoife K. O’Connell, Yu Zhang, Jin Zhong, Guocai Zhong, Florian Douam, Xinquan Wang, Ailong Huang, Rong Zhang, Qiang Ding
Abstract
SARS-CoV-2, the causative agent of pandemic COVID-19, is rapidly evolving to be more transmissible and to exhibit evasive immune properties, compromising neutralization by antibodies from vaccinated individuals or convalescent-phase sera. Recently, SARS-CoV-2 variants B.1.617.1 (Kappa), B.1.617.2 (Delta), and B.1.618 with mutations within the spike proteins were identified in India. In this study, we examined cell entry efficiencies of Kappa, Delta, and B.1.618. In addition, the variants, especially the Delta variant, exhibited expanded capabilities to use mouse, marmoset, and koala ACE2 for entry. Convalescent sera from patients infected with nonvariants showed reduced neutralization titers among the Kappa, Delta, and B.1.618 variants. Furthermore, the variants remain sensitive to ACE2-Ig decoy receptor. Our study thus could facilitate understanding how variants have increased transmissibility and evasion of established immunity and also could highlight the use of an ACE2 decoy receptor as a broad-spectrum antiviral strategy against SARS-CoV-2 variants.