A new method of immunosuppression by selective destruction of cytotoxic T cells with photodynamic effect

In this study we examined the photodynamic effect on murine performed CTLs and normal lymphocytes. As the next step, we confirmed that lymphocytes obtained from the axillar lymphnode of the mice receiving skin allografts acquired donor-specific cytotoxicity detected by a ⁵¹Cr release assay. Then we tried PDT on these cells. The results reported herein show that murine CTLs uptake larger amount of Hp than normal lymphocytes do and that Hp retention in CTLs is greater than that in normal lymphocytes. Because of this tendency photo-dependent cytotoxicity is more efficient against CTLs than against normal lymphocytes. Furthermore, alloreactive CTLs obtained from skin graft-rejecting mice was shown to be susceptible to PDT in vitro, although complete selectivity was not attained. To prevent damage to normal lymphocytes and to destroy CTLs selectively, further studies should be undertaken.