RESEARCH PAPER OncoImmunology 1:2, 141–151; March/April 2012; G 2012 Landes Bioscience T cells and T cell tumors efficiently generate antigen-specific cytotoxic T cell immunity when modified with an NKT ligand Yeonseok Chung,1,5 Young-Hee Lee,1 Yongliang Zhang,1 Natalia Martin-Orozco,1 Tomohide Yamazaki,1 Dapeng Zhou,2 Chang-Yuil Kang,4 Patrick Hwu,2 Larry W. Kwak3 and Chen Dong1,* 1Department of Immunology; Center for Cancer Immunology Research; University of Texas MD Anderson Cancer Center; Houston, TX USA; 2Department of Melanoma Medical Oncology; Center for Cancer Immunology Research; University of Texas MD Anderson Cancer Center; Houston, TX USA; 3Department of Lymphoma and Myeloma; Center for Cancer Immunology Research; University of Texas MD Anderson Cancer Center; Houston, TX USA; 4College of Pharmacy; Seoul National University; Seoul, Republic of Korea; 5Institute of Molecular Medicine; University of Texas Medical School; Houston, TX USA Keywords: cytotoxic T cell, iNKT cell, a-galactosylceramide, cellular vaccine, tumor immunity, CD1d Various Invariant NKT (iNKT) cell ligands have been shown as potent adjuvants in boosting T cell reactivates to antigens on professional APC. Non-professional APC, such as T cells, also co-expressing MHC class I and CD1d, have been © lfy2omrmpuhloam0teadtcoanp1reefsfeicniet 2niNtlKyTgliegnaenLrdatae-gaaanltaigcteonns-yslpceecraifdmicidceyt(oaetGoCxi)coTn stlyhmeiprhsuBorcfyatcees Ci(DCT1Ld). oVreascpcsoinnasteioscninwimthiicaeGeiCn-pvuivlsnoe,dwEhGec-n7e. unattractive cell vaccine carriers due to their poor immunogenicity. Here, we report that T cells as well as T cell T-cell lymphoma induced tumor-specific CTL response and suppressed the growth of EG-7 in a CD8 T cell-dependent manner. Injection of aGC-loaded CD4 T cells in mice efficiently activated iNKT cells in vivo. While T cells loaded with a class I-restricted peptide induced proliferation but not effector differentiation of antigen-specific CD8 T cells, injection of T cells co-pulsed with aGC strongly induced IFNc and Granzyme B expression in T cells and complete lysis of target cells appeared to Ddirectly ostimulate nboth oiNKT atnd cytdotoxic iCD8 sTcetlls. Of r niote, b the gueneratiton eofthis.cytotoxic T cell in vivo. Presentation of aGC and peptide on the same cells was required for optimal CTL response and vaccinating T cells response was independent of IL-4, IFNc, IL-12, IL-21 and costimulation. Our data indicate that iNKT cell can license a non-professional APC to directly trigger antigen-specific cytotoxic T cell responses, which provides an alternative cellular vaccine strategy against tumors. Introduction CD1d-restricted invariant NKT cells (iNKT) recognize glycolipid antigens presented on non-classical MHC class I-like molecule, CD1d. Recent studies revealed a crucial role of iNKT cells in the host defense against pathogens and tumors through direct interaction with microbial antigens or indirect activation.1 Moreover, iNKT cell acts as a bridge between innate and acquired immune system by regulating T cell activation and function. For instance, iNKT ligands have been shown with strong potency in enhancing T cell responses to soluble protein antigens or tumor antigens presented by professional antigen- presenting cells (APC). Co-administration of a-galactosylceramide (aGC) and protein antigens generates the antigen-specific CD4 T and CD8 T cell immunity in vivo.2,3 The generation of antigen- specific adaptive immunity depends on the activation and maturation of dendritic cells (DC) after aGC injection which triggers IFNc and TNFa expression from iNKT cells.2,4 Costimulation such as CD40 and CD80/CD86 is required for *Correspondence to: Chen Dong; Email: cdong@mdanderson.org Submitted: 08/29/11; Revised: 10/16/11; Accepted: 10/19/11 http://dx.doi.org/10.4161/onci.1.2.18479 the T cell immunity in this case.4 Furthermore, injection of DC- associated aGC induces the activation and expansion of iNKT cells and NK cells in vivo in tumor patients.5,6 Non-professional APC in immune system, such as T cells, express both MHC class I and CD1d. The expression of MHC class I on these cells may allow them to be protected from NK cell- mediated cytotoxic attack through interaction with inhibitory receptors.7 The role of CD1d expression on peripheral T cells in iNKT cell biology is not yet clear, although it is well established that CD1d expression on thymic T cells is essential for positive selection of iNKT cell.8,9 DC has been shown to be the most efficient APC for iNKT cell priming when aGC was injected as a soluble form, while other types of cell expressing CDld suppress iNKT cell activation in this condition.10 In addition to DC, vaccination with B cells copulsed with aGC and tumor-derived peptide generates an efficient anti-tumor CD8 T cell response in several murine tumor models.11 Furthermore, our recent study showed that autologous B lymphoma vaccine, manipulated to present aGC, can establish memory anti-tumor T cell immunity.12 Of note, Shimizu et al. www.landesbioscience.com OncoImmunology 141