The immune responses to human and microbial heat shock proteins in periodontal disease with and without coronary heart disease

Abstract

The human 60 kDa and microbial 65 kDa heat shock proteins (HSP) have been implicated in the pathogenesis of chronic periodontitis (P) and coronary heart disease (CHD). We have studied four male non-smoking cohorts of 81 subjects, matched for age. Group (a) consisted of a healthy group with minimal gingivitis ( n = = = = 18), group (b) were patients with P ( n = = = = 23), group (c) patients with CHD and minimal gingivitis ( n = = = = 20) and group (d) patients with CHD and P ( n = = = = 20). T cells separated from peripheral blood were found to be primed to both microbial HSP65 and human HSP60 but significant CD4, human leucocyte antigen (HLA) class II-restricted proliferative responses were found only with the human HSP60 in patients with P ( P < < < < 0·001) and CHD without ( P < < < < 0·001) or with ( P < < < < 0·00001) periodontitis. Dose-dependent inhibition of T cell proliferative responses was carried out to determine the receptors involved in recognition of HSP60 and HSP65. Monoclonal antibodies to CD14 showed inhibition of T cell proliferation stimulated by both HSP60 and HSP65, consistent with the role of CD14 as a receptor for these HSPs in P and CHD. The toll-like receptor 2 (TLR-) and TLR-4 were then studied and these showed that TLR-4 was recognized by microbial HSP65, whereas TLR-2 was recognised by human HSP60 in both P and CHD. However, a dissociation was found in the HSP60 and TLR4 interaction, as TLR4 appeared to have been recognized by HSP60 in P but not in CHD. The results suggest an autoimmune or cross-reactive CD4 + + + + class IIrestricted T cell response to the human HSP60 in P and CHD. Further studies are required to determine if there is a common epitope within HSP60 that stimulates T cell proliferation in P and CHD.

Cytokines Elicited by HSP60 in Periodontitis with and without Coronary Heart Disease

“…HSP is heat labile whereas, LPS is heat stable [8]. Stimulation of cultures with heat-treated microbial HSP65 (Figure 1(e)) and human HSP60 (Figure 1(f)) abolished the production of intracellular TNF-α.…”

“…The high degree of homology between microbial and human HSPs has led to the hypothesis that tissue damage can occur as a result of cross-reactivity between bacterial and human HSPs. Humoral and T cell responses to HSP60/65 have been demonstrated in CP [4,5,[7][8][9].…”

“…TH17 cells, which produce IL-17 and have been implicated in autoimmune and chronic inflammatory conditions such as rheumatoid arthritis, may offer an alternative to the TH1/TH2 paradigm, however, their role in atherosclerosis is similarly unclear [36]. We have previously found autoimmune or cross-reactive CD4+ class II-restricted T cell responses to the human HSP60 in CP and CHD [8]. Given the potential for innate immunity to focus adaptive immune responses, the objective of this study was to investigate the role of HSP-mediated induction of intracellular TNF-α, IFN-γ, and IL-2, IL-4 and IL-5, and IL-17 from PBMC of patients with chronic periodontitis and coronary heart disease, and to determine if these responses are related to inflammation, as reflected by CRP levels.…”

“…The lack of any significant difference in the mean fluorescence intensity of intracellular TNF-α amongst groups with periodontal disease with/without coronary artery disease following stimulation with microbial HSP65 is consistent with the lymphoproliferative responses which showed no difference between the 4 groups. Most subjects respond to microbial HSP65 and this may be a result of the ability of microbial HSP65 to stimulate both naïve and primed cells [8,31,46].…”

“…To exclude the possibility of LPS contamination affecting the production of intracellular cytokine, the microbial HSP65 and human HSP60 was heat-treated as previously described [8]. HSP is heat labile whereas, LPS is heat stable [8].…”