Evaluation of Metastasis Inhibition by ABD-IL-2 Compared to Human IL-2 in a Breast Cancer Mouse Model.

Background: Interleukin-2 (IL-2) is a well-known cytokine that plays a crucial role in stimulating immune cells, including natural killer (NK) cells and cytotoxic T cells. It has been studied as an immunotherapy for a variety of diseases, including cancer. However, due to its short serum half-life, high doses of IL-2 are required which can result in systemic toxicities like capillary leak syndrome.
Objective: To demonstrate the enhanced antitumor efficacy of Albumin Binding Domain-conjugated IL-2 (ABD-IL-2) at a lower dose compared to IL-2.
Methods: IL-2 and ABD-IL-2 were purified using Ni-NTA resin with a histidine sequence added to their C-terminal region for purification purpose. Peripheral blood lymphocytes were stimulated with IL-2 and ABD-IL-2 to assess their function. 4T1 cells were injected into BALB/c mice to establish a breast cancer model with metastasis evaluated in the lungs.
Results: Both recombinant proteins significantly stimulated T lymphocyte proliferation compared to the negative control (P=0.000, P=0.001). Administration of both proteins reduced the size of isolated tumors in the breast cancer mouse model. The control group had more nodules and larger lung metastatic centers (P=0.000). Metastasis to secondary lymphoid organs occurred only in the control group.
Conclusion: By using ABD-IL-2 at a one-third concentration compared to IL-2, we aimed to reduce administration toxicity associated with high doses of IL-2 in immunotherapy. This approach shows potential for improving IL-2-based treatments while minimizing adverse effects.