Bovine Coronavirus Hemagglutinin-esterase (HE)

Structural protein that makes short spikes at the surface of the virus. It contains receptor binding and receptor-destroying activities and mediates de-O-acetylation of N-acetyl-9-O-acetylneuraminic acid, which is probably the receptor determinant recognized by the virus on the surface of erythrocytes and susceptible cells. This receptor-destroying activity is important for virus release as it probably helps to prevent selfaggregation and ensures the efficient spread of the progeny virus from cell to cell. May serve as a secondary viral attachment protein for initiating infection, the spike protein being the major one. It seems to be a ‘luxury’ protein that is not absolutely necessary for virus infection in culture. However, its presence in the virus may alter its pathogenicity. May become a target for both the humoral and the cellular branches of the immune system.