SARS-CoV-2 continues to infect millions of people worldwide. The subvariants arising from the variant-of-concern (VOC) Omicron include BA.1, BA.1.1, BA.2, BA.2.12.1, BA.4, and BA.5. All possess multiple mutations in their Spike glycoprotein, notably in its immunogenic receptor-binding domain (RBD), and present enhanced viral transmission. The highly mutated Spike glycoproteins from these subvariants present different degrees of resistance to recognition and cross-neutralisation by plasma from previously infected and/or vaccinated individuals. We have recently shown that the temperature affects the interaction between the Spike and its receptor, the angiotensin converting enzyme 2 (ACE2). The affinity of RBD for ACE2 is significantly increased at lower temperatures. However, whether this is also observed with the Spike of Omicron and sub-lineages is not known. Here we show that, similar to other variants, Spikes from Omicron sub-lineages bind better the ACE2 receptor at lower temperatures. Whether this translates into enhanced transmission during the fall and winter seasons remains to be determined.
Keywords: ACE2 affinity; BA.4; BA.5; COVID-19; Omicron; RBD; SARS-CoV-2; Spike glycoprotein; temperature; variant of concern.