The glycoprotein of influenza C virus is the haemagglutinin, esterase and fusion factor.
Of the biological activities of influenza C virus, haemagglutination, receptor inactivation and fusion, only the latter has been conclusively correlated with its surface glycoprotein (gp). We have purified the gp by octylglucoside treatment of influenza C virions followed by centrifugation into a sucrose gradient. Evidence was obtained that gp also represents the receptor-destroying enzyme of influenza C virus, which has been characterized as a neuraminate 9-O-acetylesterase: (i) it inactivated the receptors for influenza C virus on chicken erythrocytes; (ii) it had acetylesterase activity as indicated by the release of acetate from bovine submandibulary mucin; (iii) monoclonal antibodies directed against gp inhibited the acetylesterase activity of influenza C virus. Although purified gp was unable to agglutinate chicken red blood cells, it blocked haemagglutination by viruses. This finding as well as the haemagglutination inhibition activity of monoclonal anti-gp antibodies indicate that gp is also responsible for the haemagglutinating activity of influenza C virus. Thus, as the influenza C glycoprotein is the only myxovirus glycoprotein with three different activities, we propose the designation HEF in order to describe its function as a haemagglutinin (H), an esterase (E) and a fusion factor (F).
Herrler
G
G
Institut für Virologie, Philipps-Universität Marburg, F.R.G.
Dürkop
I
I
Becht
H
H
Klenk
H D
HD
D000115:Acetylesterase; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification* / Q000494:pharmacology; D002645:Chickens; D004912:Erythrocytes; D006023:Glycoproteins / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology*; D006389:Hemagglutinins, Viral / Q000302:isolation & purification*; D009982:Gammainfluenzavirus / Q000032:analysis* / Q000276:immunology; D009975:Orthomyxoviridae / Q000032:analysis*; D011991:Receptors, Virus / Q000187:drug effects; D014760:Viral Fusion Proteins / Q000302:isolation & purification*; D014764:Viral Proteins / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology*
D000914:Antibodies, Viral; D006023:Glycoproteins; D006389:Hemagglutinins, Viral; D011991:Receptors, Virus; D014760:Viral Fusion Proteins; D014764:Viral Proteins; D002265:Carboxylic Ester Hydrolases; D000115:Acetylesterase; C046298:sialate O-acetylesterase