| Autor: |
Jakubovics, Nicholas S., Kerrigan, Steven W., Nobbs, Angela H., Strömberg, Nicklas, van Dolleweerd, Craig J., Cox, Dermot M., Kelly, Charles G., Jenkinson, Howard F. |
| Zdroj: |
Infection and Immunity; October 2005, Vol. 73 Issue: 10 p6629-6638, 10p |
| Abstrakt: |
ABSTRACTStreptococcus gordoniicolonizes multiple sites within the human oral cavity. This colonization depends upon the initial interactions of streptococcal adhesins with host receptors. The adhesins that bind salivary agglutinin glycoprotein (gp340) and human cell surface receptors include the antigen I/II (AgI/II) family polypeptides SspA and SspB and a sialic acid-binding surface protein designated Hsa or GspB. In this study we determined the relative functions of the AgI/II polypeptides and Hsa in interactions of S. gordoniiDL1 (Challis) with host receptors. For an isogenic mutant with the sspAand sspBgenes deleted the levels of adhesion to surface-immobilized gp340 were reduced 40%, while deletion of the hsagene alone resulted in >80% inhibition of bacterial cell adhesion to gp340. Adhesion of S. gordoniiDL1 cells to gp340 was sialidase sensitive, verifying that Hsa has a major role in mediating sialic acid-specific adhesion to gp340. Conversely, aggregation of S. gordoniicells by fluid-phase gp340 was not affected by deletion of hsabut was eliminated by deletion of the sspAand sspBgenes. Deletion of the AgI/II polypeptide genes had no measurable effect on hsamRNA levels or Hsa surface protein expression, and deletion of hsadid not affect AgI/II polypeptide expression. Further analysis of mutant phenotypes showed that the Hsa and AgI/II proteins mediated adhesion of S. gordoniiDL1 to human HEp-2 epithelial cells. Hsa was also a principal streptococcal cell surface component promoting adhesion of human platelets to immobilized streptococci, but Hsa and AgI/II polypeptides acted in concert in mediating streptococcal cell-platelet aggregation. The results suggest that Hsa directs primary adhesion events for S. gordoniiDL1 (Challis) with immobilized gp340, epithelial cells, and platelets. AgI/II polypeptides direct gp340-mediated aggregation, facilitate multimodal interactions necessary for platelet aggregation, and modulate S. gordonii-host engagements into biologically productive phenomena. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
