Selective IL-1 activity on CD8 + T cells empowers antitumor immunity and synergizes with neovasculature-targeted TNF for full tumor eradication.

Background: Clinical success of therapeutic cancer vaccines depends on the ability to mount strong and durable antitumor T cell responses. To achieve this, potent cellular adjuvants are highly needed. Interleukin-1β (IL-1β) acts on CD8 ⁺ T cells and promotes their expansion and effector differentiation, but toxicity and undesired tumor-promoting side effects hamper efficient clinical application of this cytokine.
Methods: This 'cytokine problem' can be solved by use of AcTakines ( Ac tivity-on- Ta rget cyto kines ), which represent fusions between low-activity cytokine mutants and cell type-specific single-domain antibodies. AcTakines deliver cytokine activity to a priori selected cell types and as such evade toxicity and unwanted off-target side effects. Here, we employ subcutaneous melanoma and lung carcinoma models to evaluate the antitumor effects of AcTakines.
Results: In this work, we use an IL-1β-based AcTakine to drive proliferation and effector functionality of antitumor CD8 ⁺ T cells without inducing measurable toxicity. AcTakine treatment enhances diversity of the T cell receptor repertoire and empowers adoptive T cell transfer. Combination treatment with a neovasculature-targeted tumor necrosis factor (TNF) AcTakine mediates full tumor eradication and establishes immunological memory that protects against secondary tumor challenge. Interferon-γ was found to empower this AcTakine synergy by sensitizing the tumor microenvironment to TNF.
Conclusions: Our data illustrate that anticancer cellular immunity can be safely promoted with an IL-1β-based AcTakine, which synergizes with other immunotherapies for efficient tumor destruction.
Competing Interests: Competing interests: Financial interests: NK and JT are affiliated and hold equity interests in Orionis Biosciences. The following patent applications are related to the work presented in this paper: WO/2015/007542: Targeted modified IL-1 family members. Applicants: VIB VZW, Universiteit Gent, Centre National de la Recherche Scientifique, Université Montpellier, Centre Hospitalier Regional Universitaire de Montpellier. Inventors: JT, SG, FP and GU This patent application describes IL-1β mutants with reduced bioactivity that can be activated by targeting. WO/2017/134306: CD8 binding agents. Applicants: Orionis Biosciences, VIB VZW, Universiteit Gent. Inventors: JT, AC, NK and SG. This patent application describes sdAbs that bind CD8 and that can be used to target mutant IL-1β to CTLs. WO/2015/007903: Targeted modified TNF family members. Applicants: VIB VZW, Universiteit Gent, Centre National de la Recherche Scientifique, Université Montpellier, Centre Hospitalier Regional Universitaire de Montpellier. This patent application describes TNF mutants with reduced bioactivity that can be activated by targeting. Inventors: JT, Jennyfer Bultinck, FP and GU. The authors have no other, nonfinancial, competing interests to declare.
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