The glycoprotein of influenza C virus is the haemagglutinin, esterase and fusion factor

J Gen Virol. 1988 Apr;69 ( Pt 4):839-46. doi: 10.1099/0022-1317-69-4-839.


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).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylesterase
  • Animals
  • Antibodies, Viral / immunology
  • Carboxylic Ester Hydrolases / isolation & purification*
  • Carboxylic Ester Hydrolases / pharmacology
  • Chickens
  • Erythrocytes
  • Glycoproteins / immunology
  • Glycoproteins / isolation & purification
  • Glycoproteins / physiology*
  • Hemagglutinins, Viral / isolation & purification*
  • Influenzavirus C / analysis*
  • Influenzavirus C / immunology
  • Orthomyxoviridae / analysis*
  • Receptors, Virus / drug effects
  • Viral Fusion Proteins / isolation & purification*
  • Viral Proteins / immunology
  • Viral Proteins / isolation & purification
  • Viral Proteins / physiology*


  • Antibodies, Viral
  • Glycoproteins
  • Hemagglutinins, Viral
  • Receptors, Virus
  • Viral Fusion Proteins
  • Viral Proteins
  • Carboxylic Ester Hydrolases
  • Acetylesterase
  • sialate O-acetylesterase