Induction of contact photosensitivity to TCSA using photohapten-modified syngeneic spleen cells.

We investigated the induction and transfer of contact photosensitivity (CPS) to the photohapten 3,3',4',5-tetrachlorosalicylanilide (TCSA) using photo-TCSA-coupled syngeneic cells in mice. PhotoTCSA-modified spleen cells (photoTCSA-SC) with efficient immunogenicity were prepared with ultraviolet A (UVA) irradiation of spleen cells suspended in TCSA solution. Subcutaneous inoculation of photoTCSA-SC into syngeneic mice induced a highly specific CPS response detected by ear swelling upon epicutaneous challenge with TCSA painting plus UVA irradiation. The sensitivity was determined to be a cell-mediated, delayed-type hypersensitivity reaction from the time course of the reactivity, the characteristic histology, and the successful transfer of the sensitivity into syngeneic naive recipients by immune lymph node T cells with the phenotype of L3T4+, Lyt-2-. In contrast to the conventional TCSA painting plus UVA irradiation method, this immunization procedure did not evoke an ordinary contact sensitivity reaction to TCSA. The present procedure represented a new way to induce CPS.

The influence of glutathione on the photoreaction of 3,4',5-tribromosalicylanilide alone and in the presence of serum albumin.

Glutathione is known to play a prominent detoxifying role in the organism. In this study attention has been paid to the possible occurrence of a detoxifying action of glutathione on the photoreaction of 3,4',5-tribromosalicylanilide (tbsa), which is notorious for causing photoallergy. It was found that tbsa forms stable photoconjugates on irradiation with glutathione: 3-glutathyl-4',5-dibromosalicylanilide and 5-glutathyl-4'-bromosalicylanilide. The rate of the photoreaction of tbsa in the presence of glutathione, resulting in photostable products, is increased. Furthermore, covalent binding with serum albumin appeared to be decreased in the presence of glutathione.