Figure 1.

Ambivalent cytokines modulating CD4⁺ T cell responses in the tumor microenvironment. IL-2 stimulates both CD4⁺, CD8⁺, and NK cells but has a greater affinity for the IL2Rαβγ expressed by Tregs. High doses of IL-2 enhance anti-tumor immune response while low doses preferentially stimulate Tregs proliferation, leading to immune suppression. Similarly, while high doses of TNFα and IL-1 have anti-tumor effects, in the lower amount, they both stimulate Th17 cells, plus Tregs for TNFα, leading to angiogenesis and immunosuppression, which favor tumor growth.