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 Balder, R.
Right arrow Articles by Lafontaine, E. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Balder, R.
Right arrow Articles by Lafontaine, E. R.

 Previous Article  |  Next Article 

Infection and Immunity, June 2007, p. 2765-2775, Vol. 75, No. 6
0019-9567/07/$08.00+0     doi:10.1128/IAI.00079-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Moraxella catarrhalis Strain O35E Expresses Two Filamentous Hemagglutinin-Like Proteins That Mediate Adherence to Human Epithelial Cells{triangledown}

Rachel Balder,1,2 Jonathan Hassel,1 Serena Lipski,1 and Eric R. Lafontaine1,2*

Department of Medical Microbiology and Immunology, University of Toledo Health Science Campus, 3055 Arlington Avenue, Toledo, Ohio 43614,1 Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia 306022

Received 12 January 2007/ Returned for modification 15 February 2007/ Accepted 9 March 2007

Two-partner secretion (TPS) systems are a family of proteins being rapidly identified and characterized in a growing number of gram-negative bacteria. TPS systems mediate the secretion of proteins, many involved in virulence traits such as hemolysis, adherence to epithelial cells, inhibition of bacterial growth, and immunomodulation of the host. A TPS system typically consists of a transporter located in the bacterial outer membrane (OM) which is responsible for the recognition and secretion of at least one large exoprotein. Two of the better-characterized TPS systems specify the Bordetella pertussis FHA and Haemophilus influenzae HMW1/HMW2 proteins. We identified three gene products of Moraxella catarrhalis strain O35E that resemble TPS proteins and designated them MhaC (transporter), MhaB1 (exoprotein), and MhaB2 (exoprotein). Western blot analysis using anti-MhaC, or antibodies reacting to both MhaB1 and MhaB2 (MhaB-reactive), revealed that these antigens are expressed in the OM of 63% of isolates tested. Mutations in the mhaC gene specifying the putative transporter of the M. catarrhalis wild-type strains O35E, O12E, and McGHS1 resulted in the absence of MhaB1/MhaB2 in the OM of mutants. These results are therefore consistent with the Mha proteins functioning as a TPS system. Furthermore, we discovered that these mhaC mutants exhibit markedly decreased binding to human epithelial cells relevant to pathogenesis by M. catarrhalis (Chang, HEp2, A549, and/or 16HBE14o–). Expression of O12E MhaC and MhaB1 in a nonadherent strain of Escherichia coli was found to increase the adherence of recombinant bacteria to HEp2 monolayers by sevenfold, thereby demonstrating that this M. catarrhalis TPS system directly mediates binding to human epithelial cells. The construction of isogenic mutants in the mhaB1 and mhaB2 genes of strain O35E also suggests that the MhaB proteins play distinct roles in M. catarrhalis adherence.

* Corresponding author. Mailing address: Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, 220 Riverbend Road, South Building Room 146, Athens, GA 30602. Phone: (706) 542-2863. Fax: (706) 542-5771. E-mail: elafon10{at}uga.edu

{triangledown} Published ahead of print on 19 March 2007.

Editor: D. L. Burns

Infection and Immunity, June 2007, p. 2765-2775, Vol. 75, No. 6
0019-9567/07/$08.00+0     doi:10.1128/IAI.00079-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Balder, R., Krunkosky, T. M., Nguyen, C. Q., Feezel, L., Lafontaine, E. R. (2009). Hag Mediates Adherence of Moraxella catarrhalis to Ciliated Human Airway Cells. Infect. Immun. 77: 4597-4608 [Abstract] [Full Text]  
  • de Vries, S. P. W., Bootsma, H. J., Hays, J. P., Hermans, P. W. M. (2009). Molecular Aspects of Moraxella catarrhalis Pathogenesis. Microbiol. Mol. Biol. Rev. 73: 389-406 [Abstract] [Full Text]  
  • Neil, R. B., Apicella, M. A. (2009). Role of HrpA in Biofilm Formation of Neisseria meningitidis and Regulation of the hrpBAS Transcripts. Infect. Immun. 77: 2285-2293 [Abstract] [Full Text]  
  • Brooks, M. J., Sedillo, J. L., Wagner, N., Laurence, C. A., Wang, W., Attia, A. S., Hansen, E. J., Gray-Owen, S. D. (2008). Modular Arrangement of Allelic Variants Explains the Divergence in Moraxella catarrhalis UspA Protein Function. Infect. Immun. 76: 5330-5340 [Abstract] [Full Text]  
  • Brooks, M. J., Sedillo, J. L., Wagner, N., Wang, W., Attia, A. S., Wong, H., Laurence, C. A., Hansen, E. J., Gray-Owen, S. D. (2008). Moraxella catarrhalis Binding to Host Cellular Receptors Is Mediated by Sequence-Specific Determinants Not Conserved among All UspA1 Protein Variants. Infect. Immun. 76: 5322-5329 [Abstract] [Full Text]  
  • van Ulsen, P., Rutten, L., Feller, M., Tommassen, J., van der Ende, A. (2008). Two-Partner Secretion Systems of Neisseria meningitidis Associated with Invasive Clonal Complexes. Infect. Immun. 76: 4649-4658 [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»