In vitro photosensitization II. An electron microscopy study of cellular destruction with mono-L-aspartyl chlorin e6 and photofrin II.

Primary sites of subcellular destruction with photofrin II (PfII) and mono-L-aspartyl chlorin e6 (MACE) were determined by transmission electron microscopy (TEM). Potorous tridactylus (PTK2) cells were grown in Rose chambers and incubated for 24 hr with a sensitizer concentration sufficient to provide 100% mortality. Cells were irradiated with laser light and fixed and processed for electron microscopy at various times post-irradiation. The results indicate that PfII initially destroys mitochondria, whereas MACE destroys lysosomes. Both conclusions are consistent with fluorescence subcellular localization studies.