Cytokines produced by CD4+ T cells against a synthetic GTF-I(1301-1322) peptide of Streptococcus mutans in naturally sensitized humans.

Streptococcus mutans (S. mutans) is the main etiological agent in dental caries. Its virulence factors are the proteins PAc and glucosyltransferase (GTF), which are related to its physiopathogenia and have been used in research for a dental caries vaccine. It was reported that using experimental animal models, GTF-I(1301-1322) synthetic peptide from the GLU region of the GTFs has Tepitopes, induces production of serum antibodies in saliva and reduces the presence of caries, but little is known about the cellular response in naturally sensitized humans. The aim of this study was to observe whether GTF-I(1301-1322) peptide is capable of activating CD4+ T cells in PBMC from naturally sensitized humans, to classify the response and to establish the relationship with dental caries. The study was conducted on 30 individuals classified into the following 3 groups: active caries (AC), History of Caries (HC), and free of caries (H). A blood sample was drawn from each individual. Specific antigen stimulation and flow cytometry analyses were used to determine cells producing the cytokines IFN-gamma (type 1 cytokine) and IL-13 (type 2 cytokine). Cell memory response to GTF-I(1301-1322) peptide was found in naturally sensitized humans. Three different responses were detected: TH0, TH1, and NR. The percentage of CD4+ T cells producing the cytokines IFN-gamma (type 1 cytokine) was greater than the percentage producing IL-13 (p=0.006). No statistically significant differences were found among the three groups for the other variables studied (p < or = 0.05). In conclusion, specific cellular immune responses against the GTF-I(1301-1322) peptide of S. mutans does not differ between individuals who are naturally sensitized, caries- resistant or with caries.