Before exposure to UV-B, wild and NF-κB-luciferase mice were anesthetized with Hypnorm-Dormicum. For the skin-exposure experiments, we exposed the shorn ventral portion of a number of transgenic mice to 1 minimal erythema dose (MED; 360 J/m2) of UV-B radiation. From 2 to 24 hours after UV-B exposure, we recorded the photons emitted, after suitable injection of luciferin substrate, through an image-intensifying high-resolution camera. For the ocular experiments, the irises of both eyes were dilated with tropicamide (0.5%), and the right eye of each mouse received UV-B radiation (λmax 295 nm) during a 15-minute period with exposure doses ranging from 0.4 to 8 kJ/m2; the left eye served as the control. The radiation apparatus consisted of an air-cooled high-pressure 100-W mercury-xenon lamp (PTI) providing light, which was collimated and directed through a water-cooled water filter, redirected through a dichroic mirror (reflecting wavelengths, <400 nm), and directed upward through an interference filter (297 FS 10-50, λ max= 295 nm, λ 0.5= 8.8 nm; Andover Corp., Salem, NH). The UV-B output (fluence rate, μW/cm2) was measured by a UV-B detector (model 7104; Oriel, Stratford, CT) that had been calibrated by the manufacturer within the previous 2 months. The light’s intensity was measured before and after each exposure.