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 HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Moayeri, M.
Right arrow Articles by Leppla, S. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Moayeri, M.
Right arrow Articles by Leppla, S. H.

 Previous Article  |  Next Article 

Infection and Immunity, November 2007, p. 5175-5184, Vol. 75, No. 11
0019-9567/07/$08.00+0     doi:10.1128/IAI.00719-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Anthrax Protective Antigen Cleavage and Clearance from the Blood of Mice and Rats{triangledown}

Mahtab Moayeri, Jason F. Wiggins, and Stephen H. Leppla*

Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892

Received 28 May 2007/ Returned for modification 19 June 2007/ Accepted 14 August 2007

Bacillus anthracis protective antigen (PA) is an 83-kDa (PA83) protein that is cleaved to the 63-kDa protein (PA63) as an essential step in binding and internalizing lethal factor (LF). To assess in vivo receptor saturating PA concentrations, we injected mice with PA variants and measured the PA remaining in the blood at various times using PA83- and PA63-specific enzyme-linked immunosorbent assays. We found that both wild-type PA (WT-PA) and a receptor-binding-defective mutant (Ub-PA) were cleaved to PA63 independent of their ability to bind cells. This suggested a PA-acting protease activity in the blood. The protease cleaved PA at the furin cleavage sequence because furin site-modified PA mutants were not cleaved. Cleavage measured in vitro was leupeptin sensitive and dependent on calcium. Cell surface cleavage was important for toxin clearance, however, as Ub-PA and uncleavable PA mutants were cleared at slower rates than WT-PA. The cell binding-independent cleavage of PA was also verified by using Ub-PA (which is still cleaved) to rescue mice from toxin challenge by competitively binding circulating LF. This mutant was able to rescue mice even when given 12 h before toxin challenge. Its therapeutic ability was comparable to that of dominant-negative PA, which binds cells but does not allow LF translocation, and to the protection afforded through receptor clearance by WT-PA and uncleavable receptor binding-competent mutants. The PA cleavage and clearance observed in mice did not appear to have a role in the differential mouse susceptibility as it occurred similarly in lethal toxin (LT)-resistant DBA/2J and LT-sensitive BALB/cJ mice. Interestingly, PA63 was not found in LT-resistant or -sensitive rats and PA83 clearance was slower in rats than in mice. Finally, to determine the minimum amount of PA required in circulation for LT toxicity in mice, we administered time-separated injections of PA and LF and showed that lethality of LF for mice after PA was no longer measurable in circulation, suggesting active PA sequestration at tissue surfaces.

* Corresponding author. Mailing address: Laboratory of Bacterial Diseases, Building 33, Room 1W20, NIAID, NIH, Bethesda, MD 20892-3202. Phone: (301) 594-2865. Fax: (301) 480-0326. E-mail: sleppla{at}niaid.nih.gov

{triangledown} Published ahead of print on 27 August 2007.

Editor: J. B. Bliska

Infection and Immunity, November 2007, p. 5175-5184, Vol. 75, No. 11
0019-9567/07/$08.00+0     doi:10.1128/IAI.00719-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Abboud, N., De Jesus, M., Nakouzi, A., Cordero, R. J. B., Pujato, M., Fiser, A., Rivera, J., Casadevall, A. (2009). Identification of Linear Epitopes in Bacillus anthracis Protective Antigen Bound by Neutralizing Antibodies. J. Biol. Chem. 284: 25077-25086 [Abstract] [Full Text]  
  • Boyer, A. E., Quinn, C. P., Hoffmaster, A. R., Kozel, T. R., Saile, E., Marston, C. K., Percival, A., Plikaytis, B. D., Woolfitt, A. R., Gallegos, M., Sabourin, P., McWilliams, L. G., Pirkle, J. L., Barr, J. R. (2009). Kinetics of Lethal Factor and Poly-D-Glutamic Acid Antigenemia during Inhalation Anthrax in Rhesus Macaques. Infect. Immun. 77: 3432-3441 [Abstract] [Full Text]  
  • Reason, D., Liberato, J., Sun, J., Keitel, W., Zhou, J. (2009). Frequency and Domain Specificity of Toxin-Neutralizing Paratopes in the Human Antibody Response to Anthrax Vaccine Adsorbed. Infect. Immun. 77: 2030-2035 [Abstract] [Full Text]  
  • Alfano, R. W., Leppla, S. H., Liu, S., Bugge, T. H., Meininger, C. J., Lairmore, T. C., Mulne, A. F., Davis, S. H., Duesbery, N. S., Frankel, A. E. (2009). Matrix Metalloproteinase-Activated Anthrax Lethal Toxin Inhibits Endothelial Invasion and Neovasculature Formation during In vitro Morphogenesis. Mol Cancer Res 7: 452-461 [Abstract] [Full Text]  
  • Tang, S., Moayeri, M., Chen, Z., Harma, H., Zhao, J., Hu, H., Purcell, R. H., Leppla, S. H., Hewlett, I. K. (2009). Detection of Anthrax Toxin by an Ultrasensitive Immunoassay Using Europium Nanoparticles. CVI 16: 408-413 [Abstract] [Full Text]  
  • Goldman, D. L., Zeng, W., Rivera, J., Nakouzzi, A., Casadevall, A. (2008). Human Serum Contains a Protease That Protects against Cytotoxic Activity of Bacillus anthracis Lethal Toxin In Vitro. CVI 15: 970-973 [Abstract] [Full Text]  
  • Liu, S., Wang, H., Currie, B. M., Molinolo, A., Leung, H. J., Moayeri, M., Basile, J. R., Alfano, R. W., Gutkind, J. S., Frankel, A. E., Bugge, T. H., Leppla, S. H. (2008). Matrix Metalloproteinase-activated Anthrax Lethal Toxin Demonstrates High Potency in Targeting Tumor Vasculature. J. Biol. Chem. 283: 529-540 [Abstract] [Full Text]  


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