ANTI-TUMOR RESPONSES INDUCED BY LASER IRRADIATION AND IMMUNOLOGICAL STIMULATION USING A MOUSE MAMMARY TUMOR MODEL

Abstract

Anti-tumor immunological response induced by local intervention is ideal for treatment of metastatic tumors. Laser immunotherapy was developed to synergize photothermal interaction with immunological stimulation for cancer treatment. Using an infrared laser, indocyanine green (ICG, as a light absorbing agent), and glycated chitosan (GC, as an immunostimulant), laser immunotherapy has resulted in tumor suppression and anti-tumor responses in pre-clinical as well as clinical studies. To further understand the mechanism of laser immunotherapy, the effects of laser and GC treatment without specific enhancement of laser absorption were studied. Passive adoptive immunity transfer was performed using splenocytes as immune cells. Spleen cells harvested from tumor-bearing mice treated by laser + GC provided 60% immunity in naive recipients. Furthermore, cytotoxicity and TNF-α secretion by splenocytes from treated mice also indicated that laser + G induced immunity was tumor-specific. The high level of infiltrating T cells in tumors after laser + GC treatment further confirmed a specific anti-tumor immune response. Therefore, laser + GC could prove to be a promising selective local treatment modality that induces a systemic anti-tumor response, with appropriate laser parameters and GC doses.

Keywords

• Laser immunotherapy
• glycated chitosan
• anti-tumor immunity
• metastatic cancers