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 Segura, M.
Right arrow Articles by Olivier, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Segura, M.
Right arrow Articles by Olivier, M.

 Previous Article  |  Next Article 

Infection and Immunity, September 2004, p. 5322-5330, Vol. 72, No. 9
0019-9567/04/$08.00+0     DOI: 10.1128/IAI.72.9.5322-5330.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Encapsulated Streptococcus suis Inhibits Activation of Signaling Pathways Involved in Phagocytosis

Mariela Segura,1,2 Marcelo Gottschalk,2,3 and Martin Olivier1,2*

Centre for the Study of Host Resistance, Research Institute of the McGill University Health Centre, and Departments of Medicine and Microbiology and Immunology, McGill University, Montréal,1 Canadian Research Network on Bacterial Pathogens of Swine,2 Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP), Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada3

Received 15 December 2003/ Returned for modification 6 April 2004/ Accepted 15 June 2004

Streptococcus suis capsular type 2 is an important zoonotic agent of meningitis. Previous studies reported that, in contrast to nonencapsulated mutants, encapsulated S. suis is able to resist phagocytosis. However, the mechanisms by which S. suis avoids phagocytosis are unknown. To elucidate the signaling pathway(s) involved in S. suis antiphagocytosis, we compared the ability of an encapsulated strain and its nonencapsulated mutant to induce the activation of Akt and protein kinase C (PKC), which are downstream kinases of the phosphatidylinositol 3-kinase (PI-3K) pathway, known to be involved in the phagocytosis processes. The results demonstrated high levels of Akt and PKC{alpha} phosphorylation after infection of J774 macrophages with the nonencapsulated mutant, whereas the encapsulated strain showed reduced activation of PI-3K/Akt/PKC{alpha} signaling pathway, as well as several protein tyrosine events. These results correlated with the number of intracellular bacteria. Macrophages pretreated with specific PI-3K or PKC inhibitors showed reduced levels of Akt and PKC{alpha} phosphorylation, resulting in 50% reduction of phagocytosis. The role of phosphatases in the antiphagocytic mechanisms was evaluated by using phosphatase inhibitors, as well as SHP-1-deficient macrophages. Only in the absence of SHP-1 did the phagocytosis of encapsulated S. suis significantly increase, leading to Akt phosphorylation levels similar to those observed with the nonencapsulated strain, indicating activation of this important SH2 domain-containing tyrosine phosphatase by encapsulated S. suis. Finally, when purified S. suis capsular polysaccharide (CPS) was added to macrophages, no phosphorylation events were observed. In addition, CPS and encapsulated S. suis were able to inhibit the uptake of the nonencapsulated mutant. These results suggest the importance of CPS in the mechanisms, whereby S. suis downmodulates phagocytosis.

* Corresponding author. Mailing address: McGill University, Department of Microbiology and Immunology, Duff Medical Bldg., 3775 University St., Montréal, Québec H3A 2B4, Canada. Phone: (514) 398-5592. Fax: (514) 398-7052. E-mail: martin.olivier{at}staff.mcgill.ca.

Editor: J. T. Barbieri

Infection and Immunity, September 2004, p. 5322-5330, Vol. 72, No. 9
0019-9567/04/$08.00+0     DOI: 10.1128/IAI.72.9.5322-5330.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Burnham, C.-A. D., Shokoples, S. E., Tyrrell, G. J. (2007). Invasion of HeLa cells by group B streptococcus requires the phosphoinositide-3-kinase signalling pathway and modulates phosphorylation of host-cell Akt and glycogen synthase kinase-3. Microbiology 153: 4240-4252 [Abstract] [Full Text]  
  • Graveline, R., Segura, M., Radzioch, D., Gottschalk, M. (2007). TLR2-dependent recognition of Streptococcus suis is modulated by the presence of capsular polysaccharide which modifies macrophage responsiveness. Int Immunol 19: 375-389 [Abstract] [Full Text]  
  • Locke, J. B., Colvin, K. M., Datta, A. K., Patel, S. K., Naidu, N. N., Neely, M. N., Nizet, V., Buchanan, J. T. (2007). Streptococcus iniae Capsule Impairs Phagocytic Clearance and Contributes to Virulence in Fish. J. Bacteriol. 189: 1279-1287 [Abstract] [Full Text]  
  • Yadav, M., Clark, L., Schorey, J. S. (2006). Macrophage's Proinflammatory Response to a Mycobacterial Infection Is Dependent on Sphingosine Kinase-Mediated Activation of Phosphatidylinositol Phospholipase C, Protein Kinase C, ERK1/2, and Phosphatidylinositol 3-Kinase. J. Immunol. 176: 5494-5503 [Abstract] [Full Text]  
  • Li, Y., Martinez, G., Gottschalk, M., Lacouture, S., Willson, P., Dubreuil, J. D., Jacques, M., Harel, J. (2006). Identification of a Surface Protein of Streptococcus suis and Evaluation of Its Immunogenic and Protective Capacity in Pigs. Infect. Immun. 74: 305-312 [Abstract] [Full Text]  
  • Mock, J. R., Vakevainen, M., Deng, K., Latimer, J. L., Young, J. A., van Oers, N. S. C., Greenberg, S., Hansen, E. J. (2005). Haemophilus ducreyi Targets Src Family Protein Tyrosine Kinases To Inhibit Phagocytic Signaling. Infect. Immun. 73: 7808-7816 [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»