Suppression of delayed-type hypersensitivity (DTH) responses in xenografts by pretreatment with ultraviolet (UV)-irradiated hepatocytes.

F344 Rat hepatocytes (HCs) that had been exposed to ultraviolet (UV) light were transplanted into the dorsal subcutaneous tissues of Balb/c mice. Four days after the transplantation, the anti-HC delayed-type hypersensitivity (DTH) response was assessed by determining the response to a direct challenge with non-irradiated HCs. The DTH response in mice transplanted with 600 J/m2-UVB-irradiated HCs was suppressed significantly compared with that with non-irradiated HCs. Furthermore, the DTH responses evoked by challenge with non-irradiated HCs were similar to those evoked by UV-irradiated HCs.