Affiliation:
1. Department of Endodontics,1
2. Clinical Research Center for Periodontal Diseases,2 School of Dentistry, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
3. Department of Biostatistics,3 and
Abstract
ABSTRACT
Chronic pulpal inflammation under caries appears to be elicited by bacterial antigens that diffuse into the pulp through dentinal tubules. This prompted the hypothesis that cytokines elicited by antigens from
Streptococcus mutans
, which frequently dominates shallow lesions, could play a major role in eliciting the initial T-cell response in the pulp. To test this, we examined the ability of
S. mutans
to stimulate T cells and elicit cytokines and used
Lactobacillus casei
, which often predominates in deep carious lesions where B cells and plasma cells predominate, as a control. In addition, the presence of cytokines in the pulp was analyzed at the mRNA level.
S. mutans
elicited potent gamma interferon (IFN-γ) responses in peripheral blood mononuclear cell cultures and reduced the CD4/CD8 ratio by promoting CD8
+
T cells. Multiple inflammatory cytokine mRNAs (IFN-γ, interleukin 4 [IL-4], and IL-10) were detected in human dental pulp. A higher prevalence of IFN-γ (67%) than IL-4 (19%) or IL-10 (29%) was obtained in shallow caries, suggesting a type 1 cytokine mechanism in early pulpitis where
S. mutans
predominates. In contrast, in deep caries no differences in cytokine frequency were observed. Furthermore, the presence of IFN-γ in the pulp correlated with the presence of
S. mutans
. The extraordinary induction of type 1 cytokines and the preferential activation of CD8
+
T cells by
S. mutans
offers an explanation for the etiology of the CD8
+
T-cell-dominant lesion in early pulpitis and suggests that
S. mutans
may have a major impact on the initial lesion and pulpal pathology.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
109 articles.
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