This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ansari, I. H. Articles by Pattnaik, A. K. Search for Related Content PubMed PubMed Citation Articles by Ansari, I. H. Articles by Pattnaik, A. K.

 Previous Article  |  Next Article 

Journal of Virology, April 2006, p. 3994-4004, Vol. 80, No. 8
0022-538X/06/$08.00+0     doi:10.1128/JVI.80.8.3994-4004.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Influence of N-Linked Glycosylation of Porcine Reproductive and Respiratory Syndrome Virus GP5 on Virus Infectivity, Antigenicity, and Ability To Induce Neutralizing Antibodies

Israrul H. Ansari, Byungjoon Kwon, Fernando A. Osorio, and Asit K. Pattnaik^*

Department of Veterinary and Biomedical Sciences and Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska 68588-0666

Received 29 August 2005/ Accepted 26 January 2006

Porcine reproductive and respiratory syndrome virus (PRRSV) glycoprotein 5 (GP5) is the most abundant envelope glycoprotein and a major inducer of neutralizing antibodies in vivo. Three putative N-linked glycosylation sites (N34, N44, and N51) are located on the GP5 ectodomain, where a major neutralization epitope also exists. To determine which of these putative sites are used for glycosylation and the role of the glycan moieties in the neutralizing antibody response, we generated a panel of GP5 mutants containing amino acid substitutions at these sites. Biochemical studies with expressed wild-type (wt) and mutant proteins revealed that the mature GP5 contains high-mannose-type sugar moieties at all three sites. These mutations were subsequently incorporated into a full-length cDNA clone. Our data demonstrate that mutations involving residue N44 did not result in infectious progeny production, indicating that N44 is the most critical amino acid residue for infectivity. Viruses carrying mutations at N34, N51, and N34/51 grew to lower titers than the wt PRRSV. In serum neutralization assays, the mutant viruses exhibited enhanced sensitivity to neutralization by wt PRRSV-specific antibodies. Furthermore, inoculation of pigs with the mutant viruses induced significantly higher levels of neutralizing antibodies against the mutant as well as the wt PRRSV, suggesting that the loss of glycan residues in the ectodomain of GP5 enhances both the sensitivity of these viruses to in vitro neutralization and the immunogenicity of the nearby neutralization epitope. These results should have great significance for development of PRRSV vaccines of enhanced protective efficacy.

---

* Corresponding author. Mailing address: E126 Beadle Center, 1901 Vine Street, University of Nebraska-Lincoln, Lincoln, NE 68588. Phone: (402) 472-1067. Fax: (402) 472-8722. E-mail: apattnaik2{at}unl.edu.

---

Journal of Virology, April 2006, p. 3994-4004, Vol. 80, No. 8
0022-538X/06/$08.00+0     doi:10.1128/JVI.80.8.3994-4004.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Risatti, G. R., Holinka, L. G., Fernandez Sainz, I., Carrillo, C., Lu, Z., Borca, M. V. (2007). N-Linked Glycosylation Status of Classical Swine Fever Virus Strain Brescia E2 Glycoprotein Influences Virulence in Swine. J. Virol. 81: 924-933 [Abstract] [Full Text]  
• Stadejek, T., Oleksiewicz, M. B., Potapchuk, D., Podgorska, K. (2006). Porcine reproductive and respiratory syndrome virus strains of exceptional diversity in eastern Europe support the definition of new genetic subtypes. J. Gen. Virol. 87: 1835-1841 [Abstract] [Full Text]