PROTECTIVE ANTIBODY RESPONSES IN JUVENILE PERIODONTITIS

Previous work completed at the Clinical Research Center for Periodontal
Diseases has indicated that antibody reactive with Actinobacillus
actinomycetemcomitans (Aa) may be protective. Aa seropositive early
onset periodontitis (EOP) patients have decreased disease severity
compared to patients lacking antibody. The specific antigen-antibody
interactions and the immune mechanisms involved in providing this
protection have not been determined. We hypothesize that antibody
responses to certain specific antigens are important in the protective
antibody response. We further hypothesize that these specific antigens
include the leukotoxin produced by Aa, and/or cell surface antigens. To
test this hypothesis we propose to examine the antibody response to the
Aa leukotoxin in EOP patients using western blots with limiting dilution
analysis. This will allow us to assess the antibody response in terms of
presence/absence of specific antibody, antibody titer, antibody class and
subclass distribution, and antibody avidity. The responses will then be
compared to the clinical status of the subjects in terms of disease
severity and extent in order to determine which antibody-antigen
interactions are important in the protective antibody response. This
requires a large number of EOP patients for study. We have already
collected sera and clinical data from 284 EOP subjects. By identifying
and characterizing the specific antibody interactions responsible for the
protective antibody response in EOP patients, a better assessment of a
patient's clinical status and prognosis may be possible. Further, this
analysis may provide insight into the pathogenesis of periodontal
destruction. The antigens involved in these interactions may also make
good candidates for an Aa vaccine.