Résumé
AIM:To explore the ability of different group B streptococci ( GBS) strains on inducing platelet activation.METHODS:Six strains of GBS, separated from the septic patients with thrombocytopenia, were used as the inducers.Light transmission aggregometry was used to measure platelet aggregation.Scanning electron microscopy ( SEM) was performed to investigate the interaction of platelets with bacteria.The expression of platelet CD62P, Toll-like receptor 2 ( TLR2) and TLR4 was determined by flow cytometry and Western blotting.Furthermore, the activity of platelet TLR2 (or TLR4) was blocked by anti-TLR2 (or anti-TLR4) monoclonal antibody, and the platelet aggregation induced by GBS was detected.RESULTS:Only 3 of 6 GBS strains isolated from the septic patients induced platelet aggregation and up-regulated the expression of CD62P and TLR2 in the platelets (P<0.05), but not TLR4.Incubation with anti-TLR2 anti-body, but not anti-TLR4 antibody, significantly blocked platelet aggregation induced by GBS.CONCLUSION:Some GBS strains from the patients are able to trigger platelet activation in vitro, and platelet TLR2 may play an important role in the interaction between GBS and platelets.