title: Successful immunotherapy with IL-2/anti-CD40 induces the chemokine-mediated mitigation of an immunosuppressive tumor microenvironment.
abstract: 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.
authors.affiliation: Laboratory of Experimental Immunology, Cancer and Inflammation Program, NCI Frederick, Frederick, MD 21702, USA.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Weiss
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Back
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Scarzello
authors.forename: Jeff J
authors.initials: JJ
authors.lastname: Subleski
authors.forename: Veronica L
authors.initials: VL
authors.lastname: Hall
authors.forename: Jimmy K
authors.initials: JK
authors.lastname: Stauffer
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Dejan
authors.initials: D
authors.lastname: Micic
authors.forename: Kory
authors.initials: K
authors.lastname: Alderson
authors.forename: William J
authors.initials: WJ
authors.lastname: Murphy
authors.forename: Robert H
authors.initials: RH
authors.lastname: Wiltrout
mesh_terms: D000818:Animals; D000906:Antibodies / Q000627:therapeutic use*; D001119:Arginase / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D019013:CD40 Antigens / Q000819:agonists* / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D018946:Chemokine CCL5 / Q000096:biosynthesis; D054370:Chemokine CXCL9 / Q000096:biosynthesis; D018925:Chemokines / Q000096:biosynthesis; D019742:Chemokines, CC / Q000096:biosynthesis; D004357:Drug Synergism; D007165:Immunosuppression Therapy / Q000379:methods*; D007376:Interleukin-2 / Q000627:therapeutic use*; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D019402:Macrophage Inflammatory Proteins / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000276:immunology / Q000628:therapy*; D054390:Receptors, CCR2 / Q000096:biosynthesis / Q000235:genetics; D018121:Receptors, Cytokine / Q000096:biosynthesis
chemical_list: D000906:Antibodies; D019013:CD40 Antigens; C095218:Ccl9 protein, mouse; C515335:Ccr2 protein, mouse; D018946:Chemokine CCL5; D054370:Chemokine CXCL9; D018925:Chemokines; D019742:Chemokines, CC; C485969:Cxcl9 protein, mouse; C104577:IP10-Mig receptor; D007376:Interleukin-2; D019402:Macrophage Inflammatory Proteins; D054390:Receptors, CCR2; D018121:Receptors, Cytokine; D001119:Arginase