T-CELL RESPONSES TO 53-KDA OUTER-MEMBRANE PROTEIN OF PORPHYROMONAS-GINGIVALIS IN HUMANS WITH EARLY-ONSET PERIODONTITIS

Patients with early-onset periodontitis (EOP) are susceptible to infec tion with periodontopathic bacteria, such as Porphyromonas gingivalis. Ag53, 53-kDa outer membrane protein of P. gingivalis, evokes strong h umoral immune responses in EOP patients. In a first step to clarify ho w host immune cells recognize Ag53, we established Ag53-specific short -term T cell lines from 22 subjects including 6 EOP patients and 16 he althy donors, using overlapping peptides based on Ag53 amino acid sequ ences. All T cell lines from active EOP patients recognized a common r egion (p141-181, especially p141-161) on Ag53, while those from health y donors showed heterogeneous specificity. p141-181 was not recognized by T cell lines established from EOP patients following therapy. A mo noclonal antibody to HSA-DRB1 inhibited Ag53-induced proliferation of most of the T cell lines. Our observations suggest that, although anti gen-presenting molecules are common in EOP patients and in healthy ind ividuals, p141-161 includes a major T cell epitope(s) on Ag53 for acti ve EOP patients but not for healthy individuals or inactive EOP patien ts. (C) American Society for Histocompatibility and Immunogenetics, 19 98 Published by Elsevier Science Inc.