The involvement of antigen-presenting cells and suppressor cells in the ultraviolet radiation-induced inhibition of secondary cytotoxic T cell sensitization.

When mice were treated with ultraviolet (UV) radiation before immunization with the skin sensitizers, trinitro-chlorobenzene or dinitrofluorobenzene, they showed greatly depressed levels of priming for a secondary in vitro cytotoxic response against haptenated cells. Because the irradiation and skin painting were done on separate sites, these results suggest that the UV radiation had a systemic effect. The priming response of irradiated mice to allogeneic stimulation was normal, indicating some antigen selectivity to the inhibitory effect of UV radiation. A defect in antigen-presenting cells, previously demonstrated in UV-irradiated mice, was found to be largely responsible for the depressed priming response observed in these animals. In addition, the UV-irradiated, immunized mice possessed suppressor cells that were capable of blocking priming for cytotoxic responses against haptenated cells in normal mice.