Streptococcus sanguis interacts with platelets in vitro to induce thrombus-like aggregation. As discovered and characterized by this project, DE 05501, this physiological response of platelets is triggered when plasma membrane receptors bind certain surface determinants on S. sanguis cells. These platelet interactive determinantion S. sanguis include the class I antigen, an adhesin, and the class II antigen a collagen-like immunodeterminant that induces platelet aggregation. Some strains also show sufficient class III activity, a presumptive ecto-ATPase. to amplify the platelet aggregation response by hydrolyzing secreted ATP from the platelet to agonist ADP. Since bacteremias with these strains of S. sanguis occur frequently through life, S. sanguis interactions with platelets in the bloodstream must be considered to be potentially thrombogenic. During the next five years we plan to identify and characterize the specificity for platelets of (i) the class I antigen as an adhesin, (ii) the class II antigen as a receptor-mediated activator and (iii) The class III, ecto-ATPase-like activity. Centra to these studies will be to (iv) isolate and characterize the platelet binding sites and receptors for the class I and II antigens of S. sanguis. We have tentatively identified the latter as GPIa. Our panel of anti- S. sanguis and anti-platelet monoclonal and polyclonal antibodies will be expanded to serve as probes of the respective interactive epitopes. As our data now suggests, (v) we will test in a rabbit model the hypothesis that the platelet contribution to vegetations in subacute bacterial endocarditis (SBE) is due to active thrombotic mechanisms triggered by S. Sanguis. If this hypothesis is confirmed, the role of S. sanguis as an etiological agent in SBE should be considered dichotomous. Adhesion of this bacterium to damaged intracardiac tissues may promote colonization and infection. In addition, S. sanguis may trigger thrombotic growth of the vegetation and thromboembolic sequellae of SBE.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE005501-09
Application #
3219467
Study Section
Oral Biology and Medicine Subcommittee 1 (OBM)
Project Start
1980-08-01
Project End
1992-11-30
Budget Start
1989-12-01
Budget End
1990-11-30
Support Year
9
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Type
Schools of Dentistry
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
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Herzberg, M C; Weyer, M W (1998) Dental plaque, platelets, and cardiovascular diseases. Ann Periodontol 3:151-60
Meyer, M W; Gong, K; Herzberg, M C (1998) Streptococcus sanguis-induced platelet clotting in rabbits and hemodynamic and cardiopulmonary consequences. Infect Immun 66:5906-14
Herzberg, M C; Meyer, M W; Kilic, A et al. (1997) Host-pathogen interactions in bacterial endocarditis: streptococcal virulence in the host. Adv Dent Res 11:69-74
Herzberg, M C; Meyer, M W (1996) Effects of oral flora on platelets: possible consequences in cardiovascular disease. J Periodontol 67:1138-42
Herzberg, M C (1996) Platelet-streptococcal interactions in endocarditis. Crit Rev Oral Biol Med 7:222-36
Erickson, P R; Herzberg, M C (1995) Altered expression of the platelet aggregation-associated protein from Streptococcus sanguis after growth in the presence of collagen. Infect Immun 63:1084-8
Erickson, P R; Herzberg, M C (1993) Evidence for the covalent linkage of carbohydrate polymers to a glycoprotein from Streptococcus sanguis. J Biol Chem 268:23780-3
Erickson, P R; Herzberg, M C (1993) The Streptococcus sanguis platelet aggregation-associated protein. Identification and characterization of the minimal platelet-interactive domain. J Biol Chem 268:1646-9