Use of UVB and UVA to induce and elicit contact photoallergy in the mouse.

The development of a contact photoallergic response in animals or humans requires irradiation of the test material. Since consumers are exposed to both UVB and UVA radiation following the use of topically applied products, we have developed a mouse ear swelling photoallergy model for the screening of potential photoallergens. This model incorporates the use of UVB, as well as UVA, radiation for the induction and elicitation phases of the photoallergic response. In this report, we show that the use of a 10 J/cm2 UVA and 45 mJ/cm2 UVB dose regimen during both the induction and elicitation phases results in an augmented photoallergic response to 6-methylcoumarin as compared with the responses of mice treated with 6-methylcoumarin and irradiated with UVA or UVB alone or UVA plus UVB radiation for induction and then UVA or UVB radiation alone at challenge. Photoallergic responses to tetrachlorosalicylanilide and musk ambrette were neither augmented nor diminished by the use of UVB radiation at induction and challenge as compared with the use of UVA treatment alone. The non-photocontact allergic response to oxazolone was reduced approximately 25% when mice were treated with oxazolone plus UVB and UVA radiation as compared with mice treated with oxazolone alone. These results suggest that in screening a test material's photoallergic potential, UVB and UVA radiation should be included for both the induction and elicitation phases of the mouse ear swelling photoallergy protocol.