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
Google Scholar
Right arrow Articles by Tian, J.
Right arrow Articles by Byrnes, A. P.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tian, J.
Right arrow Articles by Byrnes, A. P.

 Previous Article  |  Next Article 

Journal of Virology, June 2009, p. 5648-5658, Vol. 83, No. 11
0022-538X/09/$08.00+0     doi:10.1128/JVI.00082-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Adenovirus Activates Complement by Distinctly Different Mechanisms In Vitro and In Vivo: Indirect Complement Activation by Virions In Vivo{triangledown}

Jie Tian,1,{dagger} Zhili Xu,1,{dagger} Jeffrey S. Smith,1 Sean E. Hofherr,2 Michael A. Barry,2,3 and Andrew P. Byrnes1*

Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland,1 Department of Internal Medicine, Division of Infectious Diseases, Translational Immunovirology Program,2 Department of Immunology and Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota3

Received 13 January 2009/ Accepted 19 March 2009

Understanding innate immunity is key to improving the safety of adenovirus (Ad) vectors for systemic gene therapy. Ad has been shown to activate complement in vitro, but activation of complement after Ad injection in vivo has not been directly measured. Using complement protein C3a as a marker of complement activation, we show that types 2 and 5 human Ads cause rapid complement activation after intravenous injection in mice. Unexpectedly, the mechanisms in vivo were different than those in vitro. Antibodies were critical for the activation of complement by Ad in vitro, but antibodies were not required in vivo. The classical pathway was required in vitro, whereas complement activation in vivo involved both classical and nonclassical pathways as well as the reticuloendothelial system. Remarkably, the entry-deficient Ad mutant ts1 was completely unable to activate complement in vivo even though it was fully able to activate complement in vitro. This result demonstrates that the complement system senses intravenously injected Ad primarily by detecting the effects of Ad on cells rather than through direct interaction of complement with virions. Encouragingly, shielding Ad with polyethylene glycol was effective at reducing complement activation both in vitro and in vivo. In summary, intravenously injected Ad rapidly activates complement through multiple pathways, but these pathways are different than those identified by in vitro studies. In vitro studies are poorly predictive of in vivo mechanisms because Ad virions activate complement through indirect mechanisms in vivo.

* Corresponding author. Mailing address: Division of Cellular and Gene Therapies, FDA CBER, HFM-725, 8800 Rockville Pike, Bethesda, MD 20892. Phone: (301) 827-1786. Fax: (301) 827-0449. E-mail: Andrew.Byrnes{at}fda.hhs.gov

{triangledown} Published ahead of print on 25 March 2009.

{dagger} J.T. and Z.X. contributed equally to this work.

Journal of Virology, June 2009, p. 5648-5658, Vol. 83, No. 11
0022-538X/09/$08.00+0     doi:10.1128/JVI.00082-09
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»