Circulating β(1) 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 β(1) adrenoceptors (β(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 β(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 β(1) synthetic peptide. The corresponding affinity-purified anti-β(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 β(1)-AR autoantibodies are elevated in patients with CP. These autoantibodies were targeted to the fibroblasts, and specifically to the β(1)-AR, and has receptor-like activity inhibiting DNA synthesis.