While there is evidence that chronic inflammation and infection promotes plaque formation, acute infections are associated with a transient five-fold increased risk of unstable coronary and vascular syndromes caused by platelet dependent thrombosis. While many strains of bacteria induce platelet aggregation, the mechanisms by which bacteria stimulate platelets has had minimal investigation. In preliminary data utilizing comprehensive microarray analyses, and a large community cohort of almost 2,000 subjects, we found distinct patterns of platelet gene expression in patients with cardiovascular disease. While several TLRs were detected in platelets, the expression of TLR2 and IL1R in particular were increased in patients with cardiovascular disease. Importantly, the functionality of TLR in platelets was established as incubation of platelets with TLR2 ligands dose-dependently induced platelet activation and aggregation. In addition, we found enhanced platelet function and platelet-monocyte/neutrophil binding with C. pneumoniae infection in vivo, and P. gingivalis incubation. The central hypothesis of the overall program project is that