Infectious bronchitis virus spike glycoprotein (IBV S glycoprotein)

The infectious bronchitis virus spike glycoprotein is a large, trimeric, type I membrane glycoprotein protruding from the surface of the infectious bronchitis virus (IBV), a gammacoronavirus that primarily infects chickens[1][3][4]. The spike protein is composed of two functional subunits: S1, which mediates receptor binding and defines host and tissue tropism, and S2, which catalyzes membrane fusion between the viral envelope and host cell membrane, enabling viral entry[1][6]. The S1 subunit is the major determinant of antigenic diversity, often varying significantly between IBV strains and thus affecting immune recognition and vaccine efficacy[2][5]. The S protein is highly glycosylated, which influences its antigenicity and immune evasion capabilities[3]. As the key mediator for host cell entry, the spike protein is the major target for neutralizing antibodies, and sequence analysis of S1 is widely used to classify IBV genotypes and monitor vaccine escape. Despite extensive vaccination, constant evolution of the spike protein poses ongoing challenges for disease control in poultry[2][5][6].

Other names

spike protein (IBV)S proteinIBV-Scoronavirus spike glycoprotein (IBV)viral spike protein

Entry inhibition: neutralizing antibodies and experimental inhibitors prevent viral entry by blocking receptor binding or membrane fusion. Vaccination: immune response against S protein prevents viral infection.