TYPE-1 AND TYPE-2 CD8(-CELL SUBSETS ISOLATED FROM CHRONIC ADULT PERIODONTITIS TISSUE DIFFER IN SURFACE PHENOTYPE AND BIOLOGICAL FUNCTIONS()T)

Cloning of CD8(+) T cells expressing the alpha beta T-cell receptor fr om inflamed human gingiva revealed that at least two different subsets were found within the tissue and that these subsets were able to inte ract with each other. One subset produced high levels of interferon-ga mma (IFN-gamma) and no interleukin-4 (IL-4) or IL-5, exhibited phytoha emagglutinin (PHA)- or anti-CD3-mediated cytolytic activity, and were CD28(+). The other subset produced high levels of IL-4 in combination with IL-5, displayed no cytotoxicity and were CD28(-). From the latter subset CD8(+) T-cell clones were able to suppress the proliferative r esponse of cytotoxic CD8(+) T-cell clones. This suppression could be a bolished by anti-IL-4 monoclonal antibodies. However, IL-4 alone was n ot able to induce the suppression. Our results indicate that CD8(+) T cells might participate in local immune responses by the suppression o f IFN-gamma-producing cells and by favouring humoral responses via the production of IL-4 and IL-5.