Systemic antibody responses to oral microorganisms in the cynomolgus monkey: development of methodology and longitudinal responses during ligature-induced disease

Systemic antibody responses to oral microorganisms were studied during ligature-induced periodontal disease in a non-human primate (Nhp) model. Methodology was developed using ELISA techniques to assess total IgG and IgM levels in the serum from the Nhp. In addition, an ELISA was developed utilizing affinity-purified anti-human isotype reagents to detect Nhp serum antibody responses to Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia and Fusobacterium nucleatum. Results showed that the anti-human reagents detected IgG and IgM from Macaca fascicularis with an efficiency of 25-35% and 50-60%, respectively. Following ligation, groups of Nhp were treated with an immunomodulator ("Thymopentin", TP5) or placebo to examine the effect of the T-cell stimulating agent on periodontitis and host responses. No differences were noted in total serum IgG and IgM levels for individual Nhp or between groups when baseline, ligation and treatment intervals were compared. However, following ligation, 8/12 Nhp exhibited significant increases in IgG and/or IgM antibody to P. gingivalis that were coincident with increases in the percentage of this microorganism in the subgingival plaque from the ligated sites. During the treatment phase, the antibody levels in the placebo group continued to increase, while the levels in the TP5-treated group stabilized. The findings in this study indicate that the emergence of a microorganism in the subgingival plaque (P. gingivalis) during the conversion from gingivitis to progressing periodontitis in the Nhp, elicits a systemic antibody response that is specific for the microorganism.