Basic StudiesHelper Activity of Natural Killer Cells During the Dendritic Cell-mediated Induction of Melanoma-specific Cytotoxic T CellsWong, Jeffrey L.*; Mailliard, Robbie B.*,†; Moschos, Stergios J.‡,§; Edington, Howard*,§; Lotze, Michael T.*,§; Kirkwood, John M.‡,§; Kalinski, Pawel*,†,§,∥Author Information Departments of *Surgery ‡Medicine ∥Immunology †Infectious Diseases and Microbiology, University of Pittsburgh §Melanoma Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA Supported by the NIH grants CA095128, CA101944, and CA114931, and the Clinical and Translational Science Institute Multidisciplinary Predoctoral Fellowship Program (5TL1RR024155-04). All authors have declared there are no financial conflicts of interest with regard to this work. Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website, www.immunotherapy-journal.com. Reprints: Pawel Kalinski, Department of Surgery, University of Pittsburgh, Hillman Cancer Center, UPCI Research Pavilion, Room 1.46b, 5117 Center Avenue, Pittsburgh, PA 15213-1863 (e-mail: firstname.lastname@example.org). Received August 11, 2009 Accepted November 27, 2010 Journal of Immunotherapy: April 2011 - Volume 34 - Issue 3 - p 270-278 doi: 10.1097/CJI.0b013e31820b370b Buy SDC Metrics AbstractIn Brief Natural killer (NK) cells have been shown to mediate important immunoregulatory “helper” functions in addition to their cytolytic activity. In particular, NK cells are capable of preventing maturation-related dendritic cell (DC) “exhaustion,” inducing the development of “type-1 polarized” mature DCs (DC1) with an enhanced ability to produce interleukin (IL)-12p70, a factor essential for type-1 immunity and effective anticancer responses. Here we show that the NK cell-mediated type-1 polarization of DCs can be applied in the context of patients with advanced cancer to enhance the efficacy of DCs in inducing tumor-specific cytotoxic T lymphocytes. NK cells isolated from patients with late-stage (stage III and IV) melanoma responded with high interferon-γ production and the induction of type-1-polarized DCs on exposure to defined combinations of stimulatory agents, including interferon-α and IL-18. The resulting DCs showed strongly-enhanced IL-12p70 production on subsequent T-cell interaction compared with immature DCs (average of 19-fold enhancement) and nonpolarized IL-1β/TNF-α/IL-6/PGE2-matured “standard” DCs (average of 215-fold enhancement). Additional inclusion of polyinosinic: polycytidylic acid during NK-DC cocultures optimized the expression of CD80, CD86, CD40, and HLA-DR on the resulting NKDC1, increased their CCR7-mediated migratory responsiveness to the lymph node-associated chemokine CCL21, and further enhanced their IL-12-producing capacity. When compared in vitro with immature DCs and nonpolarized standard DCs, NKDC1 were superior in inducing functional melanoma-specific cytotoxic T lymphocytes capable of recognizing multiple melanoma-associated antigens and killing melanoma cells. These results indicate that the helper function of NK cells can be used in clinical settings to improve the effectiveness of DC-based cancer vaccines. Supplemental Digital Content is available in the text. © 2011 Lippincott Williams & Wilkins, Inc.