This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Buchholz, U. J.
Right arrow Articles by Collins, P. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Buchholz, U. J.
Right arrow Articles by Collins, P. L.

 Previous Article  |  Next Article 

Journal of Virology, February 2009, p. 1969-1980, Vol. 83, No. 4
0022-538X/09/$08.00+0     doi:10.1128/JVI.02041-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Deletion of Nonstructural Proteins NS1 and NS2 from Pneumonia Virus of Mice Attenuates Viral Replication and Reduces Pulmonary Cytokine Expression and Disease{triangledown}

Ursula J. Buchholz,1* Jerrold M. Ward,2 Elaine W. Lamirande,1 Britta Heinze,3 Christine D. Krempl,1,3 and Peter L. Collins1

Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892,1 Infectious Diseases Pathogenesis Section, Comparative Medicine Branch, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892,2 Institute of Virology and Immunobiology, Julius-Maximilian University, Würzburg, Germany3

Received 26 September 2008/ Accepted 21 November 2008

Pneumonia virus of mice (PVM) strain 15 causes fatal pneumonia in mice and provides a convenient model for human respiratory syncytial virus pathogenesis and immunobiology. We prepared PVM mutants lacking the genes for nonstructural proteins NS1 and/or NS2. In Vero cells, which lack type I interferon (IFN), deletion of these proteins had no effect on the efficiency of virus growth. In IFN-competent mouse embryo fibroblasts, wild-type (wt) PVM and the {Delta}NS1 virus grew efficiently and strongly inhibited the IFN response, whereas virus lacking NS2 was highly attenuated and induced high levels of IFN and IFN-inducible genes. In BALB/c mice, intranasal infection with wt PVM caused overt disease that began on day 6 and was lethal by day 9 postinoculation. In comparison, {Delta}NS1 induced transient, reduced disease, and {Delta}NS2 and {Delta}NS12 caused no disease. Thus, NS1 and NS2 are virulence factors, with NS2 being a major antagonist of the type I IFN system. The pulmonary titers of wt PVM and {Delta}NS1 were high on day 3 and increased further by day 6; in addition, expression of IFN and representative proinflammatory cytokines/chemokines and T lymphocyte-related cytokines was undetectable on day 3 but increased dramatically by day 6 coincident with the onset of disease. The titers of {Delta}NS2 and {Delta}NS12 were somewhat lower on day 3 and decreased further by day 6; in addition, these viruses induced a more circumscribed set of cytokines/chemokines (IFN, interleukin-6 [IL-6], and CXCL10) that were detected on day 3 and had largely subsided by day 6. Lung immunohistology revealed abundant PVM-positive pneumocytes and bronchial and bronchiolar epithelial cells in wt PVM- and {Delta}NS1-infected mice on day 6 compared to few PVM-positive foci with {Delta}NS2 and {Delta}NS12. These results indicate that severe PVM disease is associated with high, poorly controlled virus replication driving the expression of high levels of pulmonary IFN and a broad array of cytokines/chemokines. In contrast, in the absence of NS2, there was an early, transient innate response involving moderate levels of IFN, IL-6, and CXCL10 that restricted virus replication and prevented disease.

* Corresponding author. Mailing address: Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bldg. 50, Rm. 6505, 50 South Dr., MSC 8007, Bethesda, MD 20892-8007. Phone: (301) 594-1533. Fax: (301) 496-8312. E-mail: ubuchholz{at}niaid.nih.gov

{triangledown} Published ahead of print on 3 December 2008.

Journal of Virology, February 2009, p. 1969-1980, Vol. 83, No. 4
0022-538X/09/$08.00+0     doi:10.1128/JVI.02041-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»