Research Highlights: Immunotherapy

Abstract

ImmunotherapyVol. 1, No. 5 News & ViewsFree AccessResearch Highlights: ImmunotherapyKarsten A Pilones & Sandra DemariaKarsten A PilonesDepartment of Pathology, MSB-504, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016, USA. Search for more papers by this authorEmail the corresponding author at demars01@med.nyu.edu & Sandra Demaria† Author for correspondenceDepartment of Pathology, MSB-504, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016, USA. Search for more papers by this authorEmail the corresponding author at demars01@med.nyu.eduPublished Online:2 Sep 2009https://doi.org/10.2217/imt.09.53AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinkedInRedditEmail Evaluation of: Bricard G, Cesson V, Devevre E et al.: Enrichment of human CD4+ Vα24/Vβ11 invariant NKT cells in intrahepatic malignant tumors. J. Immunol. 182, 5140–5151 (2009).Natural killer T (NKT) cells are a small subset of lymphocytes that bear T-cell receptors (TCR) specific for the non-polymorphic CD1d molecule bound to glycolipids [1]. There is growing interest in these cells due to their unique ability to modulate immune responses in many diseases including cancer [2]. A major subset of NKT cells is referred to as invariant NKT (iNKT) cells owing to the expression of an invariant TCR; in humans Vα24Jα18/Vβ11 [2]. iNKT cells display exquisite functional reactivity to a synthetic ligand, the glycolipid α-galactosylceramide (α-GC) [2]. Studies in mouse models of cancer have shown that the administration of α-GC can activate iNKT cells to perform antitumor effector functions [2]. Most importantly, activated iNKT cells have the ability to enhance the priming of adaptive antitumor immunity, making these cells an attractive target for immunotherapy [3]. However, results of clinical studies testing the therapeutic potential of α-GC in cancer patients have been disappointing [4,5]. Defects in iNKT cells, including decreased frequencies and/or impaired functional response to ex vivo stimulation, have been observed in the peripheral blood of cancer patients, but little is known about the presence, phenotype and function of iNKT cells within tumors [4,6,7].Bricard and coworkers studied a cohort of patients, including nine with primary hepatocellular carcinoma and eight with hepatic metastases secondary to colon carcinoma (n = 4) or uveal melanoma (n = 4). For each patient, iNKT cells were analyzed in peripheral blood, tumor nodules and non-tumor-involved liver. iNKT cells were identified by staining for Vα24 and Vβ11, and the two major subset of iNKT cells – CD4+ and CD4-CD8- double-negative (DN) – were defined by flow cytometry. While iNKT cell frequencies in peripheral blood of cancer patients and healthy donors were comparable, a significant increase in the proportion of iNKT cells was found among tumor-infiltrating lymphocytes. Importantly, overall the mean frequency of iNKT cells in the liver of cancer patients was comparable with that reported in normal livers [8]. A key finding of the study was the striking enrichment for CD4+ iNKT cells in the tumors, where they represented on average 73% of Vα24+Vβ11+ cells. By contrast, CD4+ iNKT cell frequency in peripheral blood of cancer patients was comparable to healthy donors, and a modest elevation of CD4+ iNKT cells was observed among intrahepatic lymphocytes, suggesting the possibility of a progressive enrichment of CD4+ iNKT cells from the periphery to the tumor.The phenotypic polarization of tumor-infiltrating iNKT cells towards the CD4+ subset has potentially very important implications, since DN and CD4+ iNKT cells differ in their ability to produce cytokines upon α-GC stimulation. DN iNKT cells produce IFN-γ, an important antitumor cytokine, whereas CD4+ cells produce IL-4, which, by promoting Th2 responses can antagonize effective antitumor immunity [9]. Consistent with this interpretation, in mice models of adoptive transfer only the DN subset of liver-derived iNKT cells exhibited antitumor activity [10]. Although Bricard and colleagues could not perform functional assay with the iNKT cells derived from the tumors owing to their poor proliferation in vitro, they confirmed the differential ability of DN and CD4+ iNKT cells expanded from the peripheral blood of healthy donors to produce Th1 and Th2 cytokines.Findings suggest that the enrichment in CD4+ iNKT cells may contribute to local immunosuppression within the tumor. Although the small cohort of patients examined precludes definitive conclusions, the study nonetheless highlights the importance of investigating NKT cells not only in peripheral blood, but also within the tumor microenvironment in order to advance current understanding of their biology, a critical step towards the design of immunotherapies targeting these cells.Financial & competing interests disclosureSandra Demaria has received grant support from the Research Scholar award RSG-05-145-01-LIB from the American Cancer Society, NIH-R01CA113851, and from The Chemotherapy Foundation. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.No writing assistance was utilized in the production of this manuscript.Bibliography1 Spada FM, Koezuka Y, Porcelli SA: CD1d-restricted recognition of synthetic glycolipid antigens by human natural killer T cells. J. Exp. Med.188, 1529–1534 (1998).Crossref, Medline, CAS, Google Scholar2 Dhodapkar M. 2009. Harnessing human CD1d restricted T cells for tumor immunity: progress and challenges. Front. Biosci.14, 796–807 (2009).Crossref, Medline, CAS, Google Scholar3 Fujii S, Shimizu K, Hemmi H, Steinman RM: Innate Vα14(+) natural killer T cells mature dendritic cells, leading to strong adaptive immunity. Immunol. Rev.220, 183–198 (2007).Crossref, Medline, CAS, Google Scholar4 Giaccone G, Punt CJA, Ando Y et al.: A Phase I study of the natural killer T-cell ligand α-galactosylceramide (KRN7000) in patients with solid tumors. Clin. Cancer Res.8, 3702–3709 (2002).Medline, CAS, Google Scholar5 Ishikawa A, Motohashi S, Ishikawa E et al.: A Phase I study of α-galactosylceramide (KRN7000)-pulsed dendritic cells in patients with advanced and recurrent non-small cell lung cancer. Clin. Cancer Res.11, 1910–1917 (2005).Crossref, Medline, CAS, Google Scholar6 Kawano T, Nakayama T, Kamada N et al.: Antitumor cytotoxicity mediated by ligand-activated human Vα24 NKT cells. Cancer Res.59, 5102–5105 (1999).Medline, CAS, Google Scholar7 Tahir SM, Cheng O, Shaulov A et al.: Loss of IFN-γ production by invariant NK T cells in advanced cancer. J Immunol167, 4046–4050 (2001).Crossref, Medline, CAS, Google Scholar8 Kita H, Naidenko OV, Kronenberg M et al.: Quantitation and phenotypic analysis of natural killer T cells in primary biliary cirrhosis using a human CD1d tetramer. Gastroenterology123, 1031–1043 (2002).Crossref, Medline, CAS, Google Scholar9 Lee PT, Benlagha K, Teyton L, Bendelac A: Distinct functional lineages of human Vα24 natural killer T cells. J. Exp. Med.195, 637–641 (2002).Crossref, Medline, CAS, Google Scholar10 Crowe NY, Coquet JM, Berzins SP et al.: Differential antitumor immunity mediated by NKT cell subsets in vivo. J. Exp. Med.202, 1279–1288 (2005).Crossref, Medline, CAS, Google ScholarEvaluation of: Tripp CH, Sparber F, Hermans IF, Romani N, Stoitzner P: Glycolipids injected into the skin are presented to NKT cells in the draining lymph node independently of migratory skin dendritic cells. J. Immunol. 182, 7644–7654 (2009).α-galactosylceramide (α-GC) is a synthetic glycolipid that binds to CD1d molecules expressed on antigen-presenting cells. Recognition of CD1d/α-GC complexes leads to activation of invariant NK T (iNKT) cells to produce high levels of cytokines promoting the activation of other antitumor effectors, including T cells [1]. The ability of iNKT cells to activate antigen-presenting dendritic cells (DCs) and enhance IL-12 production is key to the observed adjuvant effects of α-GC. Therefore, studies in mouse models have tested the use of α-GC in combination with tumor antigen vaccines as an alternative to ‘conventional’ adjuvants that act via Toll-like receptors [2].In the current study, Tripp and colleagues investigated the potential use of localized skin administration of α-GC. They demonstrated that α-GC administered intradermally to mice leads to activation of iNKT cells in the draining lymph nodes as well as the spleen, indicating that local administration can have systemic effects. Importantly, using the model tumor antigen ovalbumin (OVA), they showed that concomitant intradermal administration of α-GC with OVA protein enhanced antigen-specific T-cell responses as compared with OVA alone. A striking difference in cytotoxic potential of OVA-specific CD8+ T cells was seen; whereas immunization with OVA alone did not elicit any killing activity in vivo, the combination of α-GC and OVA resulted in effective lysis of antigen-loaded cells in the skin-draining lymph nodes. Vaccination with α-GC and OVA protein, but not OVA alone, was successful in the prophylactic setting, in preventing the growth of B16.OVA melanoma. Similarly, in the therapeutic setting only mice receiving OVA vaccine in combination with α-GC showed a significantly enhanced survival.To determine the role of skin DCs in the ability of α-GC administered intradermally to activate iNKT cells, the authors employed immunofluorescence staining of dermal and epidermal sheets of mouse ear skin explants to show CD1d expression in all three subsets of skin DCs (intraepidermal Langerhans cells and dermal Langerin and Langerin-DCs) and its upregulation upon migration in culture. When loaded with α-GC in vitro, migratory skin DCs were able to activate NKT cells, indicating that these DCs can efficiently present glycolipid antigens. Although α-GC administered intradermally was able to reach CD1d+ DCs present in the lymph nodes and did not require presentation by skin DCs, expression of CD1d by skin DCs supports testing its administration in novel skin immunization strategies, based on the application of antigen in a cream onto barrier-disrupted skin [3]. Overall, this work provides the rationale for testing novel vaccination approaches for cancer immunotherapy.Bibliography1 Fujii S, Shimizu K, Hemmi H, Steinman RM: Innate Vα14+ natural killer T cells mature dendritic cells, leading to strong adaptive immunity. Immunol. Rev.220,183–198 (2007).Crossref, Medline, CAS, Google Scholar2 Steinman RM, Hemmi H: Dendritic cells: translating innate to adaptive immunity. Curr. Top. Microbiol. Immunol.311,17–58 (2006).Crossref, Medline, CAS, Google Scholar3 Stoitzner P, Green LK, Jung JY et al.: Tumor immunotherapy by epicutaneous immunization requires langerhans cells. J. Immunol.180,1991–1998 (2008).Crossref, Medline, CAS, Google ScholarEvaluation of: Hong C, Lee H, Park YK et al.: Regulation of secondary antigen-specific CD8+ T-cell responses by natural killer T cells. Cancer Res. 69(10), 4301–4308 (2009).NKT cells comprise a unique subset of lymphocytes with the ability to respond rapidly with robust production of Th1 and Th2 cytokines to exogenous glycolipids bound to CD1d molecules on dendritic cells (DCs) [1]. The activation of NKT cells by a synthetic ligand, the glycolipid α-galactosylceramide (α-GC), has been shown to enhance the priming of T cells by promoting the maturation of antigen-presenting DCs [2]. Little is known, however, about the function of NKT cells in the absence of exogenous stimulation. Given the important role of NKT cells in antitumor immune responses demonstrated in animal models, it is important to better understand their functions.In a series of elegant adoptive transfer experiments, Hong and coworkers present compelling data that support the NKT-mediated enhancement of secondary tumor-specific CD8+ T-cell responses in the absence of administration of exogenous glycolipids. Specifically, they demonstrated that antigen-experienced/memory CD8+ T-cells specific for the model tumor antigen ovalbumin (OVA) demonstrated more robust expansion and effector functions when transferred in recipient mice possessing NKT cells than in NKT-deficient mice. When challenged with OVA+ tumor cells, NKT-intact mice showed slower tumor growth and better survival than NKT-deficient mice, which correlated with better persistence and proliferation of the transferred OVA-specific CD8+ T cells. In vitro, NKT cells enhanced the proliferation and IFN-γ production of primed CD8+ T cells only in the presence of CD1d-expressing DCs and OVA-derived peptide antigen, implying the presence of an endogenous glycolipid expressed by DCs and capable of activating NKT cells. Interestingly, the ability of DCs to activate NKT cells was enhanced by their contact with antigen-experienced CD8 T cells, suggesting a reciprocal cross-talk coordinated by DCs.Interestingly, the authors also showed that additional activation of NKT cells by administration of α-GC during secondary antitumor responses further increased the antitumor activity of T cells previously activated by vaccination. These findings have important implications for the use of α-GC during vaccination with cancer-derived antigens, and suggest that α-GC should be given at the time of boost immunizations. In addition, they suggest that the presence of an intact repertoire of functional NKT cells may be critical for the success of adoptive immunotherapy with in vitro-expanded antitumor T cells [3].Bibliography1 Godfrey DI, Kronenberg M: Going both ways: immune regulation via CD1d-dependent NKT cells. J. Clin. Invest.114,1379–1388 (2004).Crossref, Medline, CAS, Google Scholar2 Fujii SI, Shimizu K, Smith C, Bonifaz L, Steinman RM: Activation of natural killer T cells by α-galactosylceramide rapidly induces the full maturation of dendritic cells in vivo and thereby acts as an adjuvant for combined CD4 and CD8 T cell immunity to a coadministered protein. J. Exp. Med.198,267–279 (2003).Crossref, Medline, CAS, Google Scholar3 Rosenberg SA, Restifo NP, Yang JC, Morgan RA, Dudley ME: Adoptive cell transfer: a clinical path to effective cancer immunotherapy. Nat. Rev. Cancer8,299–308 (2008).Crossref, Medline, CAS, Google ScholarFiguresReferencesRelatedDetailsCited ByAbscopal, immunological effects of radiotherapy: Narrowing the gap between clinical and preclinical experiences13 October 2017 | Immunological Reviews, Vol. 280, No. 1 Vol. 1, No. 5 Follow us on social media for the latest updates Metrics Downloaded 367 times History Published online 2 September 2009 Published in print September 2009 Information© Future Medicine LtdPDF download