{
  "abstract": "Background The strong regulatory T cell (Treg) inhibitory activity and dysfunctional cytotoxic T lymphocytes (CTLs) represent major barriers to effective antitumor immunity, particularly in late-stage cancer. Multiple anti-OX40 (aOX40) agonistic antibodies have been developed but exhibit limited antitumor efficacy. Interleukin-2 (IL-2) effectivity expands CTLs but has severe side effects.Methods We construct an aOX40-mIL2-Fc bispecific antibody through Fab physical blocking and attenuated IL-2 with Rβ reducing N88D mutation. We also produced aOX40-Fc and IL-2/aOX40-Fc as a comparison using the 293F expression system. Single-cell and flow cytometry were used to analyze the change of T-cell subsets in the tumor microenvironment (TME). Mouse tumor models were used to assess the antitumor efficacy of aOX40-mIL2-Fc by tumor growth and survival, and toxicity by body weight loss, inflammatory cytokine production, and natural killer (NK) cell proliferation in the blood. The tumor-bearing mice were randomly assigned, and the average size was similar among various groups.Results aOX40-mIL2-Fc bispecific antibody-cytokine exhibited a synergistic therapeutic effect with limited toxicity, outperforming IL-2-Fc or aOX40 alone treatment, and conferring resistance to tumor rechallenge. On cellular mechanisms, aOX40-mIL2-Fc treatment showed great Treg depletion and increased both stem-like and effector functional terminal CD8 + T cells in the TME, while avoiding NK cells expansion in the periphery. Furthermore, this bispecific antibody remarkably improved the anti-programmed death-ligand 1 (PD-L1) therapeutic effect.Conclusions Our study unveils a novel approach to IL-2 design that addresses several critical shortcomings of existing strategies and elucidates the cellular mechanisms underlying aOX40-mIL2-Fc therapy. Meanwhile, combining aOX40-mIL2-Fc with PD-L1 blockade represents a strategic approach to enhance tumor control and overcome resistance to immune checkpoint blockade therapies synergistically.",
  "authors": [
    {
      "affiliations": [
        "State Key Laboratory of Molecular Oncology and School of Basic Medical Sciences, Tsinghua University, Beijing, China"
      ],
      "name": "Shuaishuai Cao"
    },
    {
      "affiliations": [
        "Institute of Biophysics Chinese Academy of Sciences, Chaoyang, Beijing, China"
      ],
      "name": "Zhichen Sun"
    },
    {
      "affiliations": [
        "State Key Laboratory of Molecular Oncology and School of Basic Medical Sciences, Tsinghua University, Beijing, China"
      ],
      "name": "Wenbo Hu"
    },
    {
      "affiliations": [
        "State Key Laboratory of Molecular Oncology and School of Basic Medical Sciences, Tsinghua University, Beijing, China"
      ],
      "name": "Diyuan Xue"
    },
    {
      "affiliations": [
        "State Key Laboratory of Molecular Oncology and School of Basic Medical Sciences, Tsinghua University, Beijing, China"
      ],
      "name": "Zuming Yang"
    },
    {
      "affiliations": [
        "State Key Laboratory of Molecular Oncology and School of Basic Medical Sciences, Tsinghua University, Beijing, China"
      ],
      "name": "Pengfei Duan"
    },
    {
      "affiliations": [
        "Guangzhou Laboratory, Guangzhou International Bio-Island, Guangzhou, China",
        "State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China"
      ],
      "name": "Hua Peng"
    },
    {
      "affiliations": [
        "State Key Laboratory of Molecular Oncology and School of Basic Medical Sciences, Tsinghua University, Beijing, China",
        "Beijing Changping Laboratory, Beijing, Beijing, China"
      ],
      "name": "Yang-Xin Fu"
    },
    {
      "affiliations": [
        "State Key Laboratory of Molecular Oncology and School of Basic Medical Sciences, Tsinghua University, Beijing, China"
      ],
      "name": "Yong Liang"
    }
  ],
  "title": "Dual targeting OX40 and IL-2 receptor enhances antitumor activity through tumor-infiltrating Treg depletion and CD8+ T-cell proliferation",
  "uid": "68582dd2-9901-59e9-914b-ce6b4d3ac02d"
}