ABSTRACT
Ionizing radiation induces direct and indirect killing of cancer cells and for long has been considered as immunosuppressive. However, this concept has evolved over the past few years with the demonstration that irradiation can increase tumor immunogenicity and can actually favor the implementation of an immune response against tumor cells. Adoptive T-cell transfer (ACT) is also used to treat cancer and several studies have shown that the efficacy of this immunotherapy was enhanced when combined with radiation therapy. α-Radioimmunotherapy (α-RIT) is a type of internal radiotherapy which is currently under development to treat disseminated tumors. α-particles are indeed highly efficient to destroy small cluster of cancer cells with minimal impact on surrounding healthy tissues. We thus hypothesized that, in the setting of α-RIT, an immunotherapy like ACT, could benefit from the immune context induced by irradiation. Hence, we decided to further investigate the possibilities to promote an efficient and long-lasting anti-tumor response by combining α-RIT and ACT. To perform such study we set up a multiple myeloma murine model which express the tumor antigen CD138 and ovalbumine (OVA). Then we evaluated the therapeutic efficacy in the mice treated with α-RIT, using an anti-CD138 antibody coupled to bismuth-213, followed by an adoptive transfer of OVA-specific CD8+ T cells (OT-I CD8+ T cells). We observed a significant tumor growth control and an improved survival in the animals treated with the combined treatment. These results demonstrate the efficacy of combining α-RIT and ACT in the MM model we established.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Multiple Myeloma/immunology , Multiple Myeloma/therapy , Adoptive Transfer/methods , Animals , Antibodies, Monoclonal/immunology , Antigens, Neoplasm/immunology , Bismuth/immunology , Cell- and Tissue-Based Therapy/methods , Combined Modality Therapy/methods , Disease Models, Animal , Female , Mice , Mice, Inbred C57BL , Ovalbumin/immunology , Radioimmunotherapy/methods , Syndecan-1/immunologyABSTRACT
To exploit the fact that IL-2 receptors are expressed by T-cells responding to foreign antigens but not by resting T-cells, humanized anti-Tac (HAT) armed with alpha-emitting radionuclides (212)Bi and (211)At was evaluated in a cynomolgus cardiac allograft model. Control graft survival was 8.2+/- 0.5 days compared with 14.0+/-1.3 days (p<0.01) survival for monkeys treated with (212)Bi labeled HAT and 26.7+/-2.4 days survival (p<0.001 versus controls) with (211)At labeled HAT. Thus, (211)At labeled HAT may have application in organ transplantation and in treatment of IL-2 receptor expressing T-cell leukemia.
