Laser Inactivation of Blast Lymphocytes by Photodynamic Effect with Hematoporphyrin Species

Photodynamic effect caused by combination of hematoporphyrin (Hp) and photo-radiation on malignant cells, which is cytocidal, has been used as a new therapeutic modality of malignant disease. We found that cytotoxic T-cells (CTL), which play a prominent role in rejection episode in clinical organ transplantation, also possess an affinity for Hp like malignant cells. Therefore, photoradiation after administration of Hp can destroy CTL, and if we can destroy the activated CTL selectively, it has a possibility to become a new rejection therapy. We report here for the first time the photodynamic effect of Hp on human Concanavarin A (Con A) activated blast lymphocytes and mouse CTL.