Periodontal bone loss and immune characteristics after adoptive transfer of Actinobacillus‐sensitized T cells to rats

The immune response, gingival inflammation and periodontal bone loss were examined in rats receiving adoptive transfer of Actinobacillus actinomycetemcomitans (Aa) ‐sensitized T cells and oral infection with Aa. Thirty‐eight, 30‐day‐old, male Rowett phenotypically normal (rnu/+) heterozygous rats were placed into three groups: 1) Aa ‐sensitized T cell transfer group ( Aa T), 2) sham‐sensitized T cell transfer group (ST) and 3) no transfer control group (C), infected with Aa , and then sacrificed at 120 d of age. Blastogenesis of splenocytes to PHA and Con A was observed in Aa T and ST animals that exceeded the values in C animals. Positive antigenic lymphoproliferation and delayed‐type hypersensitivity (foot pad swelling) to Aa were found in Aa T group rats, but weak responses were observed in ST and C group rats. Serum IgG, salivary IgA and IgG antibody concentrations to Aa were elevated in Aa T and ST groups compared with the control group after infection with Aa. The numbers of gingival T and B lymphocytes in the Aa T group were increased in comparison to the other groups. There was also an obvious increase in horizontal bone loss in the Aa T group rats. It is suggested that certain subsets of antigen‐specific T cells may augment destructive functions on periodontal tissues.