Study Reveals New Strategies Employed By SARS-CoV-2 Variants to Evade Neutralizing Antibodies

Aug, 2021 - By SMI

A recent study led by Dr. Sebastian Fiedler, an application scientist from Cambridge U.K., revealed that emerging variants of the severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) use different strategies to escape neutralizing antibodies.

The COVID-19 pandemic continues to be a challenge for the global public health and continues to spread globally despite vaccination efforts. According to the World Health Organization’s report, approximately 194 million confirmed cases of COVID-19 including 4 million deaths were reported globally as of July 25, 2021. Although, vaccination drives have been prioritized by most of the countries with 3.71 billion doses already been administered across the globe; the emerging variants of concern pose new threat to public health globally as new emerging mutants may escape immune responses induced by vaccination or natural infection. It is alarming that variants of SARS-CoV-2 such as Alpha (B.1.1.7) and Beta (B.1.351) have raised concern as the spike glycoprotein sequences of these variants have the potential to give resistance to multiple neutralizing antibodies and improve the rate of transmission. Thus, it is very important to understand the main reason behind antibody escape of SARS-CoV-2 and its variants in order to develop effective therapeutics and vaccines to bestow broad protection. In this study, Dr. Fiedler and his team used microfluidic diffusional sizing to understand the dissociation constant related to interaction between receptor-binding domain (RBD) of the original strain of SARS-CoV-2 virus and angiotensin-converting enzyme 2 (ACE2) receptor in human cells of its alpha and beta variants.

The researchers found that for RBD-alpha, antibody escape was mainly due to increasing binding affinity to the ACE2 receptor and in case of RBD-beta, modification in key epitopes on the protein surface can be observed.