Immunological phenomena induced by UV rays

Antiserum against UV-irradiated DNA was prepared and used as a specific reagent in an indirect immunofluorescence (IF) technique for the detection of photochemically damaged DNA in the epidermis of hairless mice. Fluorescence of cell nuclei was found in sections of dorsal epidermis of mice immediately after the irradiation. It persisted for 24 hours. The IF reaction became negative after 48 hours, irrespective of the duration of UV exposure to which the mice were subjected. This may indicate: either (a) the occurrence of DNA repair processes, or (b) the relation of DNA repair to the life cycle of the epidermal cell. Mice exposed to UV radiation similar to the erythema spectrum of sunlight do not show any changes in the cellular DNA, even after a dose of 40 MED.