Change search
ReferencesLink to record
Permanent link

Direct link
Adherence and internalization of Streptococcus gordonii by epithelial cells involves beta1 integrin recognition by SspA and SspB (antigen I/II family) polypeptides.
Umeå University, Faculty of Medicine, Odontology, Cariology.
Show others and affiliations
2006 (English)In: Cellular microbiologyArticle in journal (Refereed) Published
Abstract [en]

Streptococcus gordonii is a commensal bacterium that colonizes the hard and soft tissues present in the human mouth and nasopharynx. The cell wall-anchored polypeptides SspA and SspB expressed by S. gordonii mediate a wide range of interactions with host proteins and other bacteria. In this article we have determined the role of SspA and SspB proteins, which are members of the streptococcal antigen I/II (AgI/II) adhesin family, in S. gordonii adherence and internalization by epithelial cells. Wild-type S. gordonii DL1 expressing AgI/II polypeptides attached to and was internalized by HEp-2 cells, whereas an isogenic AgI/II(-) mutant was reduced in adherence and was not internalized. Association of S. gordonii DL1 with HEp-2 cells triggered protein tyrosine phosphorylation but no significant actin rearrangement. By contrast, Streptococcus pyogenes A40 showed 50-fold higher levels of internalization and this was associated with actin polymerization and interleukin-8 upregulation. Adherence and internalization of S. gordonii by HEp-2 cells involved beta1 integrin recognition but was not fibronectin-dependent. Recombinant SspA and SspB polypeptides bound to purified human alpha5beta1 integrin through sequences present within the NAV (N-terminal) region of AgI/II polypeptide. AgI/II polypeptides blocked interactions of S. gordonii and S. pyogenes with HEp-2 cells, and S. gordonii DL1 cells expressing AgI/II proteins inhibited adherence and internalization of S. pyogenes by HEp-2 cells. Conversely, S. gordonii AgI/II(-) mutant cells did not inhibit internalization of S. pyogenes. The results suggest that AgI/II proteins not only promote integrin-mediated internalization of oral commensal streptococci by host cells, but also potentially influence susceptibility of host tissues to more pathogenic bacteria.

Place, publisher, year, edition, pages
URN: urn:nbn:se:umu:diva-12960OAI: diva2:152631
Available from: 2006-09-23 Created: 2006-09-23 Last updated: 2011-01-11Bibliographically approved

Open Access in DiVA

No full text

By organisation

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 40 hits
ReferencesLink to record
Permanent link

Direct link