Successful immunotherapy with IL-2/anti-CD40 induces the chemokine-mediated mitigation of an immunosuppressive tumor microenvironment

Proc Natl Acad Sci U S A. 2009 Nov 17;106(46):19455-60. doi: 10.1073/pnas.0909474106. Epub 2009 Nov 5.


Treatment of mice bearing orthotopic, metastatic tumors with anti-CD40 antibody resulted in only partial, transient anti-tumor effects whereas combined treatment with IL-2/anti-CD40, induced tumor regression. The mechanisms for these divergent anti-tumor responses were examined by profiling tumor-infiltrating leukocyte subsets and chemokine expression within the tumor microenvironment after immunotherapy. IL-2/anti-CD40, but not anti-CD40 alone, induced significant infiltration of established tumors by NK and CD8(+) T cells. To further define the role of chemokines in leukocyte recruitment into tumors, we evaluated anti-tumor responses in mice lacking the chemokine receptor, CCR2. The anti-tumor effects and leukocyte recruitment mediated by anti-CD40 alone, were completely abolished in CCR2(-/-) mice. In contrast, IL-2/anti-CD40-mediated leukocyte recruitment and reductions in primary tumors and metastases were maintained in CCR2(-/-) mice. Treatment of mice with IL-2/anti-CD40, but not anti-CD40 alone, also caused an IFN-gamma-dependent increase in the expression of multiple Th1 chemokines within the tumor microenvironment. Interestingly, although IL-2/anti-CD40 treatment increased Tregs in the spleen, it also caused a coincident IFN-gamma-dependent reduction in CD4(+)/FoxP3(+) Tregs, myeloid-derived suppressor cells and Th2 chemokine expression specifically within the tumor microenvironment that was not observed after treatment with anti-CD40 alone. Similar effects were observed using IL-15 in combination with anti-CD40. Taken together, our data demonstrate that IL-2/anti-CD40, but not anti-CD40 alone, can preferentially reduce the overall immunosuppressive milieu within the tumor microenvironment. These results suggest that the use of anti-CD40 in combination with IL-2 or IL-15 may hold substantially more promise for clinical cancer treatment than anti-CD40 alone.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Antibodies / therapeutic use*
  • Arginase / biosynthesis
  • CD4-Positive T-Lymphocytes / immunology
  • CD40 Antigens / agonists*
  • CD40 Antigens / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Chemokine CCL5 / biosynthesis
  • Chemokine CXCL9 / biosynthesis
  • Chemokines / biosynthesis
  • Chemokines, CC / biosynthesis
  • Drug Synergism
  • Immunosuppression Therapy / methods*
  • Interleukin-2 / therapeutic use*
  • Lymphocytes, Tumor-Infiltrating / immunology
  • Macrophage Inflammatory Proteins / biosynthesis
  • Mice
  • Mice, Inbred BALB C
  • Neoplasms / immunology
  • Neoplasms / therapy*
  • Receptors, CCR2 / biosynthesis
  • Receptors, CCR2 / genetics
  • Receptors, Cytokine / biosynthesis


  • Antibodies
  • CD40 Antigens
  • Ccl9 protein, mouse
  • Ccr2 protein, mouse
  • Chemokine CCL5
  • Chemokine CXCL9
  • Chemokines
  • Chemokines, CC
  • Cxcl9 protein, mouse
  • IP10-Mig receptor
  • Interleukin-2
  • Macrophage Inflammatory Proteins
  • Receptors, CCR2
  • Receptors, Cytokine
  • Arginase