The complement system is known to be a major effector mechanism of specific and nonspecific immunity against bacterial infections, and is thought to play a role in the pathogenesis of periodontal diseases. However, the interactions putatively pathogenic periodontal bacteria and the complement system have not been adequately studied. Recent studies indicate that several periodontal pathogens have the dual potential to both activate the complement system via the classical or alternative complement pathways and to generate proteolytic activities that could destroy individual complement proteins. It is also possible that fragments of complement proteins with biologic activity could result from bacterial mediated proteolysis of these proteins. For purposes of the proposed studies, a group of bacterial species including seven Bacteroides and two treponemes have been chosen for examination based upon their high incidence in plaque samples cultured from diseased periodontal sites and their observed ability to elicit proteolytic activity against various protein substrates in vitro.
The specific aims of the proposed research are to first examine the complement activation profiles of these selected species, and then to reexamine such profiles in the context of the organisms' abilities to release proteases that destroy individual purified complement proteins. The destruction of these proteins will be monitored by assessment of hemolytic activity and by electophoresis of radiolabelled proteins. In addition, when cleavage fragments are identified, they will be tested for appropriate biological activities. The long term objectives are to elucidate interactions between complement and periodontal pathogens that may afford protection to these organisms due to subversion of complement activation mechanisms, and which may influence inflammatory reactions in the periodontium.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
1R01DE007606-01
Application #
3221254
Study Section
Oral Biology and Medicine Study Section (OBM)
Project Start
1986-03-01
Project End
1989-02-28
Budget Start
1986-03-01
Budget End
1987-02-28
Support Year
1
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Virginia Commonwealth University
Department
Type
Schools of Dentistry/Oral Hygn
DUNS #
City
Richmond
State
VA
Country
United States
Zip Code
23298
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Schenkein, H A (1989) Failure of Bacteroides gingivalis W83 to accumulate bound C3 following opsonization with serum. J Periodontal Res 24:20-7

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