Antitumor immune responses induced by photodynamic immunotherapy in rats

摘要

Abstract: A new laser immunotherapy was used to treat metastatic mammary rat tumors. This new modality consists of three components: a near-infrared diode laser, a photosensitizer, and an immunoadjuvant. The sensitizer-adjuvant solution was injected directly to the tumor, followed by a non-invasive laser application. The new method resulted in total eradication of the treated primary tumors and eradication of untreated metastases at remote sites. Observed was the long-term survival of treated tumor-bearing rats: up to 120 days after tumor inoculation, a 300% increase in survival length compared with untreated control tumor-bearing rats. In addition, the successfully treated rats were refractory to tumor rechallenge with 10 times of the original tumor dose. Fluorescein and peroxidase immunochemical assays were also performed using sera from cured rats as the primary antibody. Strong antibody binding to both live and preserved tumor cells was observed. Western blot analysis, using the cured rat serum as primary antibody also showed distinctive protein binding, suggesting the induction of tumor-specific humoral immune response. These results indicated that an immune response was induced by the treatment of laser, photosensitizer and immunoadjuvant. !27