Matured either by IRX-2 or the Apocynin conventional cytokines were loaded with a PCI-13 cell-lysate and tested for the presence of HLA-Class-I-peptide complexes on their 
surface. These surface complexes were recognized by autologous conventional CTL and IRX-2 CTL as shown inIRX-2 Up-Regulates DC MaturationTable 1. IL-12p70 and IL-10 secretion by moDC of HD and 25033180 HNSCC patients matured with IRX-2 or the conventional Felypressin maturation cocktail.CytokineHD Conventional (mean pg/ml/105 cells EM) IRX-2 (mean pg/ml/105 cells EM) 40.367.4 14.464.4 2.p-valueIL-12p70 IL-10 Ratio of mean IL-12p70/IL-25.465.9 20.864.8 1.4 HNSCC,0.05 0.071 ,0.IL-12p70 IL-10 Ratio of mean IL-12p70/IL-10 doi:10.1371/journal.pone.0047234.t11.961.5 8.164.3 1.22.666.6 6.462.9,0.01 0.24 ,0.IFN-c ELISPOT assays. Importantly, phagocytosis of lysed tumor cells was similar in both DC preparations (data not shown). Figure 4B shows that IRX-2 CTL showed a higher number of IFN-c spots when co-incubated with IRX-2-matured DC than when incubated with conventional DC (p,0.05). The data suggest that IRX-2-matured DC are able to cross-present antigens derived from PCI-13 cells more efficiently than those matured with a conventional cytokine mixture.DiscussionIRX-2, a novel multi-component biologic, has been used for therapy of patients with HNSCC in a phase II clinical trial [13]. The therapy consisted of perilymphatically-delivered IRX-2 in combination with low-dose cyclophosphamide and a cyclooxygenase inhibitor, indomethacin, as well as zinc in a multivitamin formulation [14]. This regimen, administered prior to surgery, wasFigure 2. APM expression in mDC. moDC from HNSCC patients were matured for 48 h either with IRX-2 or the conventional maturation cocktail. (A) IRX-2-matured DC (black bars) expressed significantly higher levels of TAP1, TAP2, LMP2 and Tapasin than conventional DC (white bars, *, p,0.05). APM expression was determined by flow cytometry. The data are mean x-fold of MFI 6 SEM for cells obtained from 12 different HNSCC patients. doi:10.1371/journal.pone.0047234.gIRX-2 Up-Regulates DC MaturationFigure 3. Cytotoxicity of CTL generated 1081537 in IVS cultures. CTL were induced and expanded using iDC and DC matured either with IRX2 or the conventional cocktail from HLA-A2+ HNSCC patients. CTL primed by conventionally-matured or IRX-2-matured DC were more effective than CTL primed with iDC. CTL generated using IRX-2-matured DC showed higher cytotoxicity than those primed with conventional DC. Blocking MHC-class-I recognition with the mAb w6.32 abrogated cytotoxicity. The data are mean percentages 6 SEM of specific killing at different E:T ratios obtained from 4 independent experiments. doi:10.1371/journal.pone.0047234.gshown to increase lymphocyte infiltration into the tumor and Tcell activation in situ as compared to biopsy tissue obtained prior to treatment [13]. It also induced relatively minor but significant changes in the peripheral blood lymphocyte subsets [16]. Further, overall survival (OS) was shown to be significantly improved in the patients whose tumors were infiltrated with T cells [13]. In view of this in vivo evidence for mobilization and activation of T-cells by IRX-2, and their correlation with improved OS, we considered the possibility that IRX-2 
enhanced TA processing and presentation by DC, thereby resulting in more effective anti-tumor immunity. We tested this hypothesis using DC derived from monocytes of HNSCC patients and, specifically, evaluating IRX-2 effects on the.Matured either by IRX-2 or the conventional cytokines were loaded with a PCI-13 cell-lysate and tested for the presence of HLA-Class-I-peptide complexes on their surface. These surface complexes were recognized by autologous conventional CTL and IRX-2 CTL as shown inIRX-2 Up-Regulates DC MaturationTable 1. IL-12p70 and IL-10 secretion by moDC of HD and 25033180 HNSCC patients matured with IRX-2 or the conventional maturation cocktail.CytokineHD Conventional (mean pg/ml/105 cells EM) IRX-2 (mean pg/ml/105 cells EM) 40.367.4 14.464.4 2.p-valueIL-12p70 IL-10 Ratio of mean IL-12p70/IL-25.465.9 20.864.8 1.4 HNSCC,0.05 0.071 ,0.IL-12p70 IL-10 Ratio of mean IL-12p70/IL-10 doi:10.1371/journal.pone.0047234.t11.961.5 8.164.3 1.22.666.6 6.462.9,0.01 0.24 ,0.IFN-c ELISPOT assays. Importantly, phagocytosis of lysed tumor cells was similar in both DC preparations (data not shown). Figure 4B shows that IRX-2 CTL showed a higher number of IFN-c spots when co-incubated with IRX-2-matured DC than when incubated with conventional DC (p,0.05). The data suggest that IRX-2-matured DC are able to cross-present antigens derived from PCI-13 cells more efficiently than those matured with a conventional cytokine mixture.DiscussionIRX-2, a novel multi-component biologic, has been used for therapy of patients with HNSCC in a phase II clinical trial [13]. The therapy consisted of perilymphatically-delivered IRX-2 in combination with low-dose cyclophosphamide and a cyclooxygenase inhibitor, indomethacin, as well as zinc in a multivitamin formulation [14]. This regimen, administered prior to surgery, wasFigure 2. APM expression in mDC. moDC from HNSCC patients were matured for 48 h either with IRX-2 or the conventional maturation cocktail. (A) IRX-2-matured DC (black bars) expressed significantly higher levels of TAP1, TAP2, LMP2 and Tapasin than conventional DC (white bars, *, p,0.05). APM expression was determined by flow cytometry. The data are mean x-fold of MFI 6 SEM for cells obtained from 12 different HNSCC patients. doi:10.1371/journal.pone.0047234.gIRX-2 Up-Regulates DC MaturationFigure 3. Cytotoxicity of CTL generated 1081537 in IVS cultures. CTL were induced and expanded using iDC and DC matured either with IRX2 or the conventional cocktail from HLA-A2+ HNSCC patients. CTL primed by conventionally-matured or IRX-2-matured DC were more effective than CTL primed with iDC. CTL generated using IRX-2-matured DC showed higher cytotoxicity than those primed with conventional DC. Blocking MHC-class-I recognition with the mAb w6.32 abrogated cytotoxicity. The data are mean percentages 6 SEM of specific killing at different E:T ratios obtained from 4 independent experiments. doi:10.1371/journal.pone.0047234.gshown to increase lymphocyte infiltration into the tumor and Tcell activation in situ as compared to biopsy tissue obtained prior to treatment [13]. It also induced relatively minor but significant changes in the peripheral blood lymphocyte subsets [16]. Further, overall survival (OS) was shown to be significantly improved in the patients whose tumors were infiltrated with T cells [13]. In view of this in vivo evidence for mobilization and activation of T-cells by IRX-2, and their correlation with improved OS, we considered the possibility that IRX-2 enhanced TA processing and presentation by DC, thereby resulting in more effective anti-tumor immunity. We tested this hypothesis using DC derived from monocytes of HNSCC patients and, specifically, evaluating IRX-2 effects on the.
