The S protein of bovine coronavirus is a hemagglutinin recognizing 9-O-acetylated sialic acid as a receptor determinant

Abstract

The S protein of bovine coronavirus (BCV) has been isolated from the viral membrane and purified by gradient centrifugation. Purified S protein was identified as a viral hemagglutinin. Inactivation of the cellular receptors by sialate 9-O-acetylesterase and generation of receptors by sialylation of erythrocytes with N-acetyl-9-O-acetylneuraminic acid (Neu5,9Ac2) indicate that S protein recognizes 9-O-acetylated sialic acid as a receptor determinant as has been shown previously for intact virions. The second glycoprotein of BCV, HE, which has been thought previously to be responsible for the hemagglutinating activity of BCV, is a less efficient hemagglutinin; it agglutinates mouse and rat erythrocytes, but in contrast to S protein, it is unable to agglutinate chicken erythrocytes, which contain a lower level of Neu5,9Ac2 on their surface. S protein is proposed to be responsible for the primary attachment of virus to cell surface receptors. The potential of S protein as a probe for the detection of Neu5,9Ac2-containing glycoconjugates is demonstrated.

Antigenic and cellular localisation analysis of the severe acute respiratory syndrome coronavirus nucleocapsid protein using monoclonal antibodies

“…Virus cultures were incubated at 37 • C, 5% CO 2 or 34 • C (NL63) until a cytopathic effect was visible (229E, NL63, MHV, TGEV). For the non-cytopathic CoV OC43, virus infection was tested by hemagglutination assay (Schultze et al, 1991). Infected cells were harvested and sedimented by centrifugation.…”

Molecular and antigenic characterization of bovine Coronavirus circulating in Argentinean cattle during 1994–2010

“…Viral particles are large (100-150 nm), pleomorphic and enveloped with four major structural proteins comprising a membrane (M) glycoprotein, an envelope (E) protein, a spike (S) glycoprotein and the hemagglutinin-esterase (HE) glycoprotein (Lai, 2001). It is interesting to note that the hemagglutinating activity of the HE from BCoVs strains is lower than the hemagglutinating activity of the S glycoprotein, which forms large spike-like projections in the viral envelope (Schultze et al, 1991). Moreover, the S glycoprotein harbors domains responsible for receptor binding and induction of neutralizing antibodies, and is the most polymorphic viral protein among CoV species and also among strains of the same species.…”

Detection and characterization of bovine-like coronaviruses from four species of zoo ruminants

“…The S1 subunit is associated with binding to host cell receptors, whereas the S2 subunit is the viral M protein that mediates the fusion of viral and cellular membranes. Thus, S protein is critical for virus entry and pathogenesis (Schultze et al, 1991b). The variation in host range and tissue tropism among CoV is largely attributable to variations in the S protein (Gallagher and Buchmeier, 2001).…”