Effective Combination of Innate and Adaptive Immunotherapeutic Approaches in a Mouse Melanoma Model.

Most cancer immunotherapies include activation of either innate or adaptive immune responses. We hypothesized that the combined activation of both innate and adaptive immunity will result in better antitumor efficacy. We have previously shown the synergy of an agonistic anti-CD40 mAb (anti-CD40) and CpG-oligodeoxynucleotides in activating macrophages to induce tumor cell killing in mice. Separately, we have shown that a direct intratumoral injection of immunocytokine (IC), an anti-GD2 Ab linked to IL-2, can activate T and NK cells resulting in antitumor effects. We hypothesized that activation of macrophages with anti-CD40/CpG, and NK cells with IC, would cause innate tumor destruction, leading to increased presentation of tumor Ags and adaptive T cell activation; the latter could be further augmented by anti-CTLA-4 Ab to achieve tumor eradication and immunological memory. Using the mouse GD2(+) B78 melanoma model, we show that anti-CD40/CpG treatment led to upregulation of T cell activation markers in draining lymph nodes. Anti-CD40/CpG + IC/anti-CTLA-4 synergistically induced regression of advanced s.c. tumors, resulting in cure of some mice and development of immunological memory against B78 and wild type B16 tumors. Although the antitumor effect of anti-CD40/CpG did not require T cells, the antitumor effect of IC/anti-CTLA-4 was dependent on T cells. The combined treatment with anti-CD40/CpG + IC/anti-CTLA-4 reduced T regulatory cells in the tumors and was effective against distant solid tumors and lung metastases. We suggest that a combination of anti-CD40/CpG and IC/anti-CTLA-4 should be developed for clinical testing as a potentially effective novel immunotherapy strategy.

Journal of immunology (Baltimore, Md. : 1950). 2017 Jan 06 [Epub]

Alexander L Rakhmilevich, Mildred Felder, Lauren Lever, Jacob Slowinski, Kayla Rasmussen, Anna Hoefges, Tyler J Van De Voort, Hans Loibner, Alan J Korman, Stephen D Gillies, Paul M Sondel

Department of Human Oncology, University of Wisconsin, Madison, WI 53705; This email address is being protected from spambots. You need JavaScript enabled to view it.., Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53705., Department of Human Oncology, University of Wisconsin, Madison, WI 53705., Apeiron Biologics Inc., 1030 Vienna, Austria., Bristol-Myers Squibb Company, Redwood City, CA 94063., Provenance Biopharmaceuticals, Carlisle, MA 01741; and.