Spike glycoprotein of SARS-CoV-2 Omicron XBB.1.5

The spike glycoprotein of SARS-CoV-2 Omicron XBB.1.5 is a large, trimeric, viral envelope glycoprotein encoded by the S gene of the Omicron XBB.1.5 subvariant of SARS-CoV-2. The spike’s primary functions are mediating viral entry into host cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor and facilitating the fusion of viral and cellular membranes[4][8][12]. The protein is composed of two functional subunits: S1, responsible for receptor binding, and S2, which drives membrane fusion[8]. XBB.1.5 is marked by numerous mutations in the receptor-binding domain and fusion core, increasing binding affinity for ACE2 and conferring significant resistance to neutralizing antibodies and prior immune responses, thereby enhancing viral spread and immune evasion[3][5][7][13]. Spike glycoprotein is the main target for vaccines, therapeutic monoclonal antibodies, and is a critical determinant of SARS-CoV-2 transmission, tissue tropism, and pathogenicity[4][8]. In XBB.1.5, mutations notably decrease the effectiveness of many previously developed neutralizing antibodies and monoclonal antibody therapies, posing a challenge for treatment and prevention strategies[5][7][13].

Other names

Spike protein (S protein)Spike glycoprotein (S)S glycoproteinSARS-CoV-2 spikeCoronavirus spike proteinSurface glycoprotein

Antibodies: Neutralize spike by blocking receptor (ACE2) binding or interfering with conformational changes required for viral entry. Entry inhibitors: Prevent membrane fusion by disrupting HR1-HR2 interactions in S2.