A Combination of Systemic and Intracranial Anti-CD25 Immunotherapy Elicits a Long-Time Survival in Murine Model of Glioma

Abrogating the suppression of glioma-infiltrating Tregs in the periphery and the central nervous system is essential to successful glioma rejection. We sought to improve the immune response in glioma-bearing mice, by investigating new strategies using the anti-CD25 immunotherapy. We found a complete long-term survival of glioma-bearing mice treated with a combination of systemic and intracranial anti-CD25 mAb immunotherapy as compared to systemic administration of anti-CD25 mAb. In addition, the group of mice that had been cured by the combined anti-CD25 mAb showed long-term survival without late tumor relapse when challenged with the GL261 glioma. The antitumor immune response was investigated by analysis of antitumor immune response (CTL). Results showed that the use of the combined injections of anti-CD25 mAb induced efficient targeting of Tregs expansion inside and outside of the brain and altered Tregs trafficking in the bone marrow and brain areas where antitumor immunity was primed.