Inflammation driven by tumour-specific Th1 cells protects against B-cell cancer

ARTICLE Received 10 Nov 2010 | Accepted 15 Feb 2011 | Published 15 Mar 2011 DOI: 10.1038/ncomms1239 Inflammation driven by tumour-specific Th1 cells protects against B-cell cancer Ole Audun Werner Haabeth1, Kristina Berg Lorvik1, Clara Hammarström2, Ian M. Donaldson3,4, Guttorm Haraldsen2, Bjarne Bogen1 & Alexandre Corthay1 The immune system can both promote and suppress cancer. Chronic inflammation and proinflammatory cytokines such as interleukin (IL)-1 and IL-6 are considered to be tumour promoting. In contrast, the exact nature of protective antitumour immunity remains obscure. Here, we quantify locally secreted cytokines during primary immune responses against myeloma and B-cell lymphoma in mice. Strikingly, successful cancer immunosurveillance mediated by tumour-specific CD4 + T cells is consistently associated with elevated local levels of both proinflammatory (IL-1α, IL-1β and IL-6) and T helper 1 (Th1)-associated cytokines (interferon-γ (IFN-γ), IL-2 and IL-12). Cancer eradication is achieved by a collaboration between tumourspecific Th1 cells and tumour-infiltrating, antigen-presenting macrophages. Th1 cells induce secretion of IL-1β and IL-6 by macrophages. Th1-derived IFN-γ is shown to render macrophages directly cytotoxic to cancer cells, and to induce macrophages to secrete the angiostatic chemokines CXCL9/MIG and CXCL10/IP-10. Thus, inflammation, when driven by tumourspecific Th1 cells, may prevent rather than promote cancer. Centre for Immune Regulation, Institute of Immunology, University of Oslo and Oslo University Hospital Rikshospitalet, PO Box 4950 Nydalen, 0424 Oslo, Norway. 2 Department of Pathology, Institute of Pathology, Oslo University Hospital Rikshospitalet and University of Oslo, PO Box 4950 Nydalen, 0424 Oslo, Norway. 3 The Biotechnology Centre of Oslo, University of Oslo, PO Box 1125 Blindern, 0317 Oslo, Norway. 4 Department of Molecular Biosciences, University of Oslo, PO Box 1041 Blindern, 0316 Oslo, Norway. Correspondence and requests for materials should be addressed to A.C. (email: ). 1 nature communications | 2:240 | DOI: 10.1038/ncomms1239 | www.nature.com/naturecommunications © 2011 Macmillan Publishers Limited. All rights reserved.  ARTICLE T nature communications | DOI: 10.1038/ncomms1239 he immune system can protect against cancer1. Elevated numbers of intratumoral T cells predict long-term survival for patients with advanced ovarian carcinoma and colorectal cancer2,3. Yet, little is known about the exact nature of protective antitumour immune responses. On the other hand, it is well established that chronic inflammation predisposes to cancer. Proinflammatory cytokines such as interleukin (IL)-1 and IL-6 are considered to be essential for tumour progression, and anti-inflammatory drugs have been suggested to treat cancer4–9. However, anti-inflammatory treatments may potentially suppress protective antitumour immunity. Strategies to fight malignancies should be based on stimulating rather than suppressing the ongoing immune response against cancer. Therefore, it is crucial to better understand the interplay between immune cells, inflammation and cancer. Tumour-specific CD4 + T cells orchestrate the immune response against cancer. CD4 + T cells are required for cytokine-mediated activation of tumour-specific cytotoxic CD8 + T cells, but they can also eliminate cancer in the absence of CD8 + T cells10,11. A recent study of patients with breast cancer concluded that high numbers of CD4 + T cells in lymph nodes (LNs) predict disease-free survival12. In lung and liver cancer, high CD4:CD8 T-cell ratios were associated with good prognosis13,14. However, CD4 + T cells may also suppress antitumour immunity15. To clarify the mechanism of cancer prevention by CD4 + T cells, we have used idiotype (Id)-specific T-cell receptor transgenic (TCR-TG) mice, which were made homozygous for the severe combined immunodeficiency (SCID) mutation to prevent rearrangement of endogenous TCR chains11. In these mice, tumour-specific CD4 + T cells recognize an Id peptide from the variable region of the immunoglobulin light chain of the MOPC315 myeloma, presented on major histocompatibility complex (MHC) class II molecules16. Id-specific TCR-TG SCID mice are resistant against subcutaneous (s.c.) inoculation with syngeneic MOPC315 myeloma cells or with Id-transfected F9 B-lymphoma cells, whereas non-transgenic mice develop fatal tumours. Protection is Id-specific, CD4 + T cell-mediated, and does not require the presence of B cells and CD8 + T cells11,17. To study the mechanisms of cancer rejection by Id-specific TCR-TG mice, we have developed a strategy consisting of embedding injected tumour cells in a collagen gel (Matrigel). The Matrigel functions as an extracellular matrix in which infiltrating immune cells can be analysed at various time points after injection. Using this method, we have reported the first characterization of a successful primary antitumour immune response initiated by naïve CD4 + T cells18. In brief, we could show that s.c. injected MOPC315 myeloma cells were surrounded within 3 days by macrophages, which captured tumour-specific antigens. Within 6 days, naïve Id-specific CD4 + T cells became activated in draining LN and subsequently migrated to the incipient tumour site. On recognition of tumour-derived Id peptides presented on MHC class II molecules by macrophages, Id-specific CD4 + T cells were shown to secrete interferon-γ (IFN-γ). Matrigel-infiltrating macrophages became acti vated by T cell-derived IFN-γ, and could kill MHC class II-negative myeloma cells directly18. However, in this previous report the exact function of IFN-γ was not fully defined and the involvement of other cytokines was not investigated. In this study, we have further developed the Matrigel assay to quantify locally secreted cytokines during primary antitumour immune responses. Using this method, we uncovered a common core of nine cytokines that were consistently associated with success ful cancer immunosurveillance. Strikingly, this core includes both proinflammatory (IL-1α, IL-1β and IL-6) and T helper (Th)1-associated (IL-2, IL-3, IL-12, IFN-γ, CXCL9 and CXCL10) cytokines. Twelve additional cytokines were associated with cancer prevention in most, but not all experimental settings investigated. Thus, we have identified a total of 21 cytokines, which may serve as a basis to develop cytokine-based immunotherapy for cancer. Furthermore,  we provide evidence for a dual antitumour role of Th1-derived IFN-γ. First, IFN-γ triggers tumouricidal activity of tumour-infiltrating macrophages. Second, IFN-γ induces macrophages to secrete the angiostatic chemokines CXCL9/MIG (monokine induced by IFN-γ) and CXCL10/IP-10 (IFN-γ inducible protein 10), which may halt tumour progression by inhibiting angiogenesis. Collectively, our data suggest a cancer-protective role of inflammation driven by tumour-specific Th1 cells. Results The Matrigel cytokine assay. (...truncated)