Thymocyte activating factor(s) in human gingival fluids.

Human gingival fluid contains a low-molecular-weight factor (10,000 to 25,000) which enhances the proliferation of murine thymocytes in the presence of suboptimal doses of mitogen. Although the gingival fluid has no Interleukin 2 (T cell growth factor) activity, as indicated by its inability to induce proliferation of an IL 2 dependent lymphocytic cell line, it is directly mitogenic for dermal fibroblasts. These studies suggest that the thymocyte and fibroblast growth-promoting properties of human gingival fluid may have important functions in regulating inflammatory responses in the human periodontal tissues.