The role of Streptococcus gordonii surface proteins SspA/B and Hsa in platelet function

S Kerrigan, NS Jakubovics, C Keane, P Maguire, K Wynne, HF Jenkinson, D Cox

Research output: Contribution to journalArticle (Academic Journal)peer-review

64 Citations (Scopus)


Streptococcus gordonii colonization of damaged heart surfaces in infective endocarditis is dependent upon the recognition of host receptors by specific bacterial surface proteins. However, despite several attempts to identify the mechanisms involved in this interaction, the nature of the bacterial proteins required remains poorly understood. This study provides clear evidence that several S. gordonii surface proteins participate in the interaction with platelets to support platelet adhesion and induce platelet aggregation. S. gordonii strains were found to support strong (DL1-Challis, SK12, SK184, and Blackburn) or moderate (UB1545 {Delta}hsa and CH1-Challis) adhesion or failed to support platelet adhesion (M5, M99, and Channon). In addition, under flow conditions, platelets rolled and subsequently adhered to immobilized S. gordonii at low shear (50 s–1) in an Hsa-dependent manner but did not interact with S. gordonii DL1 at any shear rate of >50 s–1. S. gordonii strains either induced (DL1-Challis, SK12, SK184, UB1545 {Delta}hsa, and M99) or failed to induce (M5, CH1-Challis, Channon, and Blackburn) platelet aggregation. Using a proteomic approach to identify differential cell wall protein expression between aggregating (DL1) and nonaggregating (Blackburn) strains, we identified antigen I/antigen II family proteins SspA and SspB. The overexpression of SspA or SspB in platelet-nonreactive Lactococcus lactis induced GPIIb/GPIIIa-dependent platelet aggregation similar to that seen with S. gordonii DL1. However, they failed to support platelet adhesion. Thus, S. gordonii has distinct mechanisms for supporting platelet adhesion and inducing platelet aggregation. Differential protein expression between strains may be important for the pathogenesis of invasive diseases such as infective endocarditis.
Translated title of the contributionThe role of Streptococcus gordonii surface proteins SspA/B and Hsa in platelet function
Original languageEnglish
Pages (from-to)5740 - 5747
Number of pages8
JournalInfection and Immunity
Volume75 (12)
Publication statusPublished - Dec 2007

Bibliographical note

Publisher: American Society for Microbiology


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