[Human corneal fibroblasts and a human conjunctival cell line (Chang) produce a thymocyte-activating factor (TAF) in vitro].

A variety of distinct cells such as fibroblasts, epidermal cells, glioblastoma cells and corneal epithelial cells have been shown to produce Interleukin 1-like thymocyte-activating factors. Under in vitro conditions these cytokines influence a multiplicity of different cell types, including lymphocytes, fibroblasts, PMN and hepatocytes. In the present study human corneal fibroblasts, as well as the human epitheloid conjunctival Chang cell line were found to produce thymocyte-activating factors (TAF). The molecular weight of the corneal fibroblasts-TAF was found in the 670 kD region, with minor peaks of activity at 30, 17 and 4 kD. TAF from the Chang-cell line eluted at 15-25 kD. Chromatofocusing revealed the pI of the fibroblast-TAF to be at 6.7 and 5.2 and the pI of the conjunctival cells to be at 7.0, 5.3 and 5.0. The latter cells produced prostaglandin E2 upon stimulation. The immunomodulating properties of these cytokines make an important in vivo role in the pathogenesis of inflammatory corneal and conjunctival diseases probable.