Abstract
Photoimmuno therapy (PIT) is a new molecular-targeted phototherapy in which an antibody conjugated with IR700 (Ab-
IR700), a phthalocyanine derivative, is administered followed by irradiation with near-infrared light. PIT causes cell death due to cell membrane damage, and the formation of aggregates of Ab-IR700 on the cell membrane by photochemical reactions is an important mechanism of cell killing. It has also been shown that the formation of radical anion of IR700 and its protonation are necessary for the progress of this photochemical reaction. In this article, the characteristics and therapeutic mechanisms of PIT will be reviewed, and in particular, our recent findings on photochemistry will be presented for future drug development.