Interleukin 4 (IL-4) and IL-6-producing memory T-cells in peripheral blood and gingival tissues in periodontitis patients with high serum antibody titers to Porphyromonas gingivalis

We assessed cytokine production and proliferation of memory T-cells that were isolated from peripheral blood of adult periodontitis patients with high anti- Porphyromonas gingivalis titer. Memory T-cells were stimulated with P. gingivalis lipopolysaccharide, sonicates and formalin-killed whole cells. Interleukin 4 (IL-4)- and IL-6-producing cells were stained by immunocytochemically on peripheral blood smears and compared with cryostat sections of autologous gingival biopsies. Memory T-cells in the peripheral blood of patients rated significantly higher than in healthy subjects (32.3±7.1 vs 25,3±3.0%). Stimulation of patient-derived memory T-cells with P. gingivalis whole cells induced higher IL-4 production than in healthy subjects (4.4±4.1% vs 0.7±0.6%). Induction of IL-4-producing memory T-cells by P. gingivalis lipopolysaccharide and whole cells was respectively 1.37 and 1.56 times that induced by medium alone. IL-6 production did not differ between the groups. Proliferation of memory T-cells in healthy subjects tended to be more inhibited by P. gingivalis antigens than that in patients. In some patients, induction of IL-4- and IL-6-producing memory T-cells in peripheral blood and in autologous gingival biopsies tended to coincide. Memory T-cells with functional characteristics of Th2 could be a crucial cell population capable of reflecting individual susceptibility to periodontitis.