Avian infectious bronchitis virus spike glycoprotein (IBV S protein)

The **Avian infectious bronchitis virus spike glycoprotein** (IBV S protein) is a large, heavily glycosylated type I membrane protein present on the surface of the infectious bronchitis virus, a highly contagious avian coronavirus. This protein is post-translationally cleaved into two non-covalently bound subunits, S1 and S2: S1 forms the tip of the viral spike and is primarily responsible for attachment to host cell receptors, while S2 anchors S1 to the virion membrane and enables membrane fusion during viral entry[1][2][7]. The S1 subunit is the main determinant of viral infectivity, pathogenicity, serotype specificity, and induces neutralizing antibodies, making it a key vaccine and diagnostic target[2][3][4]. The S protein’s high antigenic diversity, particularly in the S1 region, results in significant challenges for effective immunization and control due to frequent vaccine escape and variable cross-protection between serotypes[2][4][6][8]. The protein is not a classical pharmacologic receptor, but is considered a primary therapeutic and vaccine target for the prevention of avian infectious bronchitis in poultry[1][2][6].

Other names

IBV spike proteinSpike (S) glycoproteinInfectious bronchitis virus S proteinAvian coronavirus S protein

Blockade of virus-host cell attachment (neutralizing monoclonal antibodies and vaccines) Induction of adaptive immune response (vaccines)