Infiltration by inflammatory cells required for solar-simulated ultraviolet radiation enhancement of skin tumor growth.
In this study we compared the effects of subinflammatory and inflammatory doses of solar-simulated ultraviolet (UV) radiation on enhancement of skin tumor growth, sensitization to haptens and cellular changes within the epidermis of C3H/HeN mice. Tumors transplanted into mice 3 days after exposure to inflammatory, but not subinflammatory, doses of UV radiation had a higher growth rate than those tumors inoculated into unirradiated control mice. Both doses of UV radiation suppressed the induction of contact hypersensitivity and induced tolerance when hapten was painted onto the skin 3 days after irradiation. Skin exposed to the higher, but not the lower, dose of UV radiation contained significantly increased numbers of CD11b+, CD45+ MHC class II- and CD45+ MHC class II(hi) inflammatory cells 3 days post-irradiation. The immunosuppression correlated with a reduction in Langerhans cells and dendritic epidermal T cells. Collectively, this suggests that suppression to contact sensitizers is due to the UV radiation effects on Langerhans cells and dendritic epidermal T cells. While these effects may also suppress the induction of anti-tumor immunity, at higher doses of UV radiation inflammatory cells may enhance tumor growth by a non-immunological mechanism.
Sluyter
R
R
Department of Medicine (Dermatology), Melanoma and Skin Cancer Research Institute, University of Sydney, Royal Prince Alfred Hospital, Sydney, Australia.
Halliday
G M
GM
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000209:etiology / Q000378:metabolism; D003877:Dermatitis, Contact; D005434:Flow Cytometry; D007249:Inflammation; D017493:Leukocyte Common Antigens / Q000096:biosynthesis; D016177:Macrophage-1 Antigen / Q000096:biosynthesis; D008285:Major Histocompatibility Complex; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D012878:Skin Neoplasms / Q000209:etiology* / Q000378:metabolism*; D016082:Solar System; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays
D016177:Macrophage-1 Antigen; D017493:Leukocyte Common Antigens