SUPPRESSION OF DELAYED AND CONTACT HYPERSENSITIVITY RESPONSES IN MICEHAVE DIFFERENT UV DOSE RESPONSES

Although acute exposure to UV radiation suppresses the induction of de layed-type (DTH) and contact (CHS) hypersensitivity in mice, it is not clear whether the photobiological mechanism(s) involved in suppressin g these closely related immune reactions is the same. A careful examin ation of the UV dose responses and wavelength dependencies involved in suppressing CHS and DTH may provide important insights into the mecha nisms involved. We compared the UV dose-response curves for suppressin g four closely related immune reactions, local and systemic suppressio n of CI-IS to dinitrofluorobenzene, systemic suppression of DTH to Can dida albicans and systemic suppression of DTH to alloantigen using thr ee different UV spectra (FS40 sunlamps, Kodacel-filtered FS40 sunlamps and solar-simulated light). For each immune response studied, the amo unt of UVB radiation required to induce 50% immune suppression was low est when FS40 sunlamps were used, highest with solar-simulated light a nd intermediate when Kodacel-filtered FS40 sunlamps were used, but the differences observed were not statistically significant. The UV dose- response curves for immune suppression differed significantly dependin g on the assay used, the site of antigenic sensitization and the antig en used. These findings suggest that the mechanisms by which UV radiat ion induces immune suppression differ for the four immunological react ions studied.