Severe acute respiratory syndrome coronavirus 2 Spike glycoprotein (Omicron BA.5 variant) (SARS-CoV-2 S protein (BA.5))

The SARS-CoV-2 Spike (S) protein of the Omicron BA.5 subvariant is a class I viral fusion protein that mediates host cell entry by binding to the Angiotensin-Converting Enzyme 2 (ACE2) receptor [1]. It is the primary antigen targeted by the human adaptive immune system following infection or vaccination, specifically through the production of neutralizing antibodies and the activation of T-cell responses [2]. The BA.5 variant is characterized by specific mutations in the receptor-binding domain (RBD), such as L452R and F486V, which contribute to increased transmissibility and significant evasion of neutralizing antibodies elicited by earlier vaccine formulations or infections [3]. Consequently, this protein was the focus of bivalent mRNA vaccine boosters designed to broaden the immune response against circulating Omicron lineages [4]. Therapeutic interventions targeting the S protein include monoclonal antibodies, although many have lost efficacy against BA.5 due to its mutational profile [5].

Other names

Spike proteinS proteinSurface glycoproteinOmicron BA.5 SpikeSARS-CoV-2 S protein

Vaccines utilize mRNA or viral vectors to induce host expression of the Spike protein, which serves as an antigen to stimulate B-cell and T-cell responses [2]. Monoclonal antibodies target the Spike protein's receptor-binding domain (RBD) to block its interaction with the ACE2 receptor, thereby neutralizing the virus [5].