Tumor-susceptibility generated in mice treated with subcarcinogenic doses of 8-methoxypsoralen and long-wave ultraviolet light.

Type:Uv phototherapy Time:2015-03-31 16:56:12

Roberts LK, Schmitt M, Daynes RA.

Abstract

Evidence is presented to show that mice treated with various regimens of 8-methoxypsoralen followed by exposure to

long-wave ultraviolet light (PUVA) are rendered tumor-susceptible when challenged with short-wave ultraviolet light

(UVB) induced regressor tumors. These same tumors are readily rejected when implanted into normal syngeneic

animals. Similar observations have been made in mice treated with subcarcinogenic doses of UVB, where it was shown

that the tumor-susceptible state is mediated by suppressor T lymphocytes. These suppressor T-cells may be generated

in response to antigens expressed by UVB damaged skin cells. It is now known that suppressor T-cells generated in

mice treated with UVB are Ia-positive and have specificities for cross-reacting tumor antigens shared by all UVB-

induced tumors, which have been tested to date. Our data suggest that, like UVB treated mice, treatment of mice

with PUVA results in tumor-susceptibility mediated through the generation of Ia+ suppressor cells. Since PUVA

treatments appear to generate a suppressor cell response in mice, a possible mechanism by which these treatments

act to manage autoimmune type skin diseases, such as vitiligo, is discussed

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