Abstract
IL-12, one of the cytokines produced in human skin by UV-B exposure, has recently been reported to enhance UV-induced DNA repair. In this study human keratinocyte cell line (HaCaT) was irradiated with UV-B at physiological dose rate, and the repair kinetics of DNA photoproducts was examined by ELISA. The amount of cyclobutane pyrimidine dimer (CPD) removed in 6h following the irradiation was significantly increased by the presence of IL-12 in a dose-dependent manner. No such effect of IL-12 was observed on repair of (6-4)photoproduct. The number of survived cells after UV-B irradiation, as revealed by colony forming ability, was also increased by IL-12. These results suggested that IL-12 accelerated the repair of CPD in UV-B irradiated keratinocytes, resulting in prevention from cell death.
