T cell responses to 53-kDa outer membrane protein of Porphyromonas gingivalis in humans with early-onset periodontitis.

Abstract Patients with early-onset periodontitis (EOP) are susceptible to infection with periodontopathic bacteria, such as Porphyromonas gingivalis. Ag53, 53-kDa outer membrane protein of P. gingivalis , evokes strong humoral immune responses in EOP patients. In a first step to clarify how host immune cells recognize Ag53, we established Ag53-specific short-term T cell lines from 22 subjects including 6 EOP patients and 16 healthy donors, using overlapping peptides based on Ag53 amino acid sequences. All T cell lines from active EOP patients recognized a common region (p141–181, especially p141–161) on Ag53, while those from healthy donors showed heterogeneous specificity. p141–181 was not recognized by T cell lines established from EOP patients following therapy. A monoclonal antibody to HLA-DRB1 inhibited Ag53-induced proliferation of most of the T cell lines. Our observations suggest that, although antigen-presenting molecules are common in EOP patients and in healthy individuals, p141–161 includes a major T cell epitope(s) on Ag53 for active EOP patients but not for healthy individuals or inactive EOP patients. Human Immunology, 59, 635–643 (1998) © American Society for Histocompatibility and Immunogenetics, 1998. Published by Elsevier Science Inc.