In vitro lymphocyte blastogenic responses and titers of humoral antibodies from periodontitis patients to oral spirochete isolates.

Humoral antibodies and in vitro blastogenic responses of patients with moderate to advanced periodontitis and of orally healthy (control) individuals to 11 spirochetes were assayed. Eight isolates of Treponema denticola, two isolates of T. vincentii, and one isolate of T. phagedenis were grown anaerobically, sonicated, and centrifuged to remove cellular debris. The blastogenic responses of peripheral blood lymphocytes were measured by [3H]-thymidine uptake. Antibody titers (immunoglobulins A, G, and M) to the spirochetes were measured with the micro-enzyme-linked immunosorbent assay. Dark-field microscopic enumeration of spirochetes was made from subgingival plaque. Spirochetes comprised 20% of the total number of microorganisms seen in plaque from the patients, whereas no spirochetes were seen in plaque from the controls. The blastogenic responses to the spirochetes were not statistically different (P greater than 0.05) between patients and controls. The immunoglobulin G and M antibody titers of the patients were generally lower than the titers of the controls, but the differences were rarely statistically significant. In contrast, the patients possessed significantly higher immunoglobulin A titers to seven spirochetes (T. denticola). No correlation was found between the percentage of spirochetes in the plaque sample and the blastogenic responses or titers of antibodies from an individual to the 11 spirochetes.