Circulating β1 Adrenergic Autoantibodies from Patients with Chronic Periodontitis Interact with Gingival Fibroblasts

OBJECTIVES To demonstrate the presence of circulating autoantibodies (Abs) from patients with chronic periodontitis (CP) that interacted with human gingival fibroblast membranes activating beta(1) adrenoceptors (beta(1)-AR). METHODS Sera and purified IgG from 25 patients with CP and 20 age-matched healthy subjects were studied by flow cytometry, ELISA and DNA synthesis. Human gingival fibroblast membranes and/or synthetic peptides with amino acid sequences identical to human beta(1)-AR were used as antigens. RESULTS By flow cytometry and ELISA procedures, we proved that the serum-purified IgG fraction from patients with CP reacted with the fibroblast surface and to the beta(1) synthetic peptide. The corresponding affinity-purified anti-beta(1) peptide Abs displayed agonist-like activity associated with specific receptor activation, inhibiting the DNA synthesis of human gingival fibroblasts. CONCLUSIONS This study demonstrates that beta(1)-AR autoantibodies are elevated in patients with CP. These autoantibodies were targeted to the fibroblasts, and specifically to the beta(1)-AR, and has receptor-like activity inhibiting DNA synthesis.