Removal of N-linked Carbohydrates Decreases the Infectivity of Herpes Simplex Virus Type 1

• Published in: Journal of general virology Vol. 69; no. 11; pp. 2847 - 2858
• Main Authors: Kuhn, Joachim E, Eing, Bodo R, Brossmer, Reinhard, Munk, Klaus, Braun, Rudiger W
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.11.1988; Society for General Microbiology
• Subjects: Adsorption; Animals; Biological and medical sciences; Cell Line; Fundamental and applied biological sciences. Psychology; Glycoconjugates - physiology; Glycoside Hydrolases - metabolism; Glycosylation; herpes simplex virus 1; Immunoblotting; Microbiology; Molecular Weight; Protein Processing, Post-Translational - drug effects; Replicative cycle, interference, host-virus relations, pathogenicity, miscellaneous strains; Simplexvirus - pathogenicity; Structure-Activity Relationship; Tunicamycin - pharmacology; Viral Envelope Proteins - metabolism; Virology; Virus; Herpesvirus hominis 1; Enzyme; Herpesviridae; Oligosaccharide; Infectivity; Alphaherpesvirinae; Glycoproteins; Glycosylation
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-69-11-2847

1 Institute for Medical Virology, University of Heidelberg, Im Neuenheimer Feld 324, 6900 Heidelberg and 2 Institute for Biochemistry II, University of Heidelberg, Im Neuenheimer Feld 328, 6900 Heidelberg, F.R.G. Purified preparations of herpes simplex virus type 1 Angelotti were digested with the exoglycosidases sialidase, -galactosidase, N -acetyl- - D -glucosaminidase and -mannosidase, and with the endoglycosidases Endo-H and Endo-F. It was found that treatment of virions with Endo-F specifically decreased viral infectivity by a factor of 10. This reduction in titre was not associated with any measurable differences in virus adsorption, suggesting a role of N -linked complex type oligosaccharide chains in penetration. In contrast, a reduction in titre observed upon digestion of virions with exoglycosidases could be attributed to a proteolytic contamination in these enzyme preparations. Treatment of virions with Endo-H, demonstrated to be free of proteolytic contamination, did not reduce viral infectivity. Analysis of endoglycosidase-digested virions by monospecific antibodies and immunoblotting revealed a susceptibility of all four major glycoproteins (gC, gB, gE and gD) to Endo-F, but only gB was susceptible to Endo-H treatment. In contrast, of all the exoglycosidases used only sialidase was found to be active towards native viral glycoproteins. Upon analysis of endoglycosidase-digested virions we could not find any evidence for proteolysis, degradation or altered protein composition of viral envelopes. In contrast, vigorous inhibition of glycoprotein glycosylation by tunicamycin led to the formation of physically intact virions almost completely lacking all major glycoproteins. These data show that digestion of intact virions with glycosidases allows an analysis of the functional relevance of carbohydrate residues without any obvious alterations in the virion glycoprotein composition. Keywords: HSV, glycoproteins, infectivity Received 5 April 1988; accepted 25 July 1988.