{
  "abstract": "Background Interleukin-2 (IL-2) immunotherapy can induce durable tumor remissions, but its clinical performance has been limited by significant drawbacks such as short serum half-life and high toxicity. Administration of IL-2 in complex with certain anti-IL-2 antibodies (IL-2cx) enhances circulation half-life while also selectivity directing the cytokine to particular immune cell subsets. In particular, IL-2cx has been developed that targets either cells expressing the CD25-containing high-affinity IL-2 receptor (ie, CD25-biased IL-2cx) or cells expressing the CD25-lacking intermediate-affinity IL-2 receptor (ie, CD25-blocking IL-2cx). Since regulatory T (Treg) cells primarily express the high-affinity IL-2 receptor whereas naïve effector T and natural killer cells mainly express the low-affinity IL-2 receptor, CD25-blocking IL-2cx have traditionally been considered as potential cancer therapeutics, particularly in combination with immune checkpoint inhibitors (ICIs).Methods Stimulation of antigen-primed T cells by IL-2cx in the absence or presence of ICIs was evaluated through adoptive transfer of primed ovalbumin-specific T cells and analysis of expansion. Effects of IL-2cx on Treg cell-mediated inhibition of CD8 + T cells were assessed by flow cytometry and thymidine incorporation. Tumor-bearing mice received combination treatments comprizing IL-2cx and ICIs, where complexes were delivered either before or after ICIs. Tumor growth and mouse survival were monitored, and immune cell phenotyping was performed. Toxicity was determined by tracking body weight, temperature, and lung edema. Substitution of IL-2cx with single-agent cytokine/antibody fusion proteins (immunocytokines, ICs) was also explored.Results We showed that CD25-biased IL-2cx and ICs synergize with ICIs to completely eradicate large, established tumors despite robust Treg cell expansion. Importantly, we found that timing is crucial, as administration of IL-2cx after (but not before) ICIs led to profound antitumor effects. Mechanistically, CD25-biased IL-2cx selectively stimulated expansion and effector functions of tumor-specific CD8 + T cells in a CD25-dependent manner, overcoming Treg cell-mediated suppression. Moreover, CD25-biased IL-2cx showed much lower toxicity than CD25-blocking IL-2cx, enabling a larger therapeutic window. Furthermore, we demonstrated that administration of a human IL-2-based IC significantly enhanced the antitumor activity of ICIs, establishing the translational relevance of our work.Conclusions Our findings support the temporally optimized use of CD25-biased IL-2-based therapeutics in combination with ICIs for cancer immunotherapy.",
  "authors": [
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Irfan Baki Kilic"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Petra Weberova"
    },
    {
      "affiliations": [
        "Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA",
        "Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA"
      ],
      "name": "Derek VanDyke"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Milada Sirova"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Katerina Kubesova"
    },
    {
      "affiliations": [
        "Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA",
        "Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland, USA"
      ],
      "name": "Charina S Fabilane"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Vladyslav Mazhara"
    },
    {
      "affiliations": [
        "Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA",
        "Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA"
      ],
      "name": "Kathy Liu"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Katerina Behalova"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Bohumil Ptacek"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Blanka Rihova"
    },
    {
      "affiliations": [
        "Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA",
        "Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA",
        "Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA",
        "Bloomberg~Kimmel Institute for Cancer Immunotherapy, Johns Hopkins University, Baltimore, Maryland, USA",
        "Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, USA",
        "Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA",
        "Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA",
        "Department of Molecular Microbiology & Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA"
      ],
      "name": "Jamie B Spangler"
    },
    {
      "affiliations": [
        "Laboratory of Tumor Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic"
      ],
      "name": "Marek Kovar"
    }
  ],
  "title": "Temporal optimization of CD25-biased IL-2 agonists and immune checkpoint blockade leads to synergistic anticancer activity despite robust regulatory T cell expansion",
  "uid": "85408b4d-a82a-5daf-b692-5049b7fcb5d4"
}