In contrast, the percentage of total NK cells and CD16+ NK cells did not change during therapy, which is in line with what was found for cetuximab (Figures 5C,D). Open in a separate window FIGURE 5 Change within the rate of recurrence of circulating CD39+Tregs and CD3-CD56+ NK cells during nimotuzumab treatment. carried out to quantify EGFR-specific T cells in nimotuzumab-treated head and neck malignancy (HNSCC) individuals. Nimotuzumab was able to destroy EGFR+ tumor cells by NK cell-mediated ADCC. Nimotuzumab-activated NK cells advertised DC maturation and EGFR-specific CD8+ T cell priming. Interestingly, nimotuzumab led to upregulation of some immune checkpoint molecules on NK cells (TIM-3) and DC (PD-L1), to a lower degree than another EGFR mAb, cetuximab. Furthermore, circulating EGFR-specific T cells were recognized in nimotuzumab-treated HNSCC individuals. Notably, nimotuzumab combined with cisplatin-based chemotherapy and radiation increased the rate of recurrence of peripheral CD4+CD39+FOXP3+Tregs which normally were decreased to baseline ideals when nimotuzumab was used as monotherapy. The rate of recurrence of circulating NK cells remained constant OTS964 during treatment. Nimotuzumab-induced, NK cell-mediated DC priming led to induction of anti-EGFR specific T cells in HNSCC individuals. The association between EGFR-specific T cells and individual medical benefit with nimotuzumab treatment should be investigated. and for setting by combining an antiproliferative, antiangiogenic and proapoptotic effect upon tumors cells that overexpress the EGFR (Crombet-Ramos et al., 2002). In the medical setting, nimotuzumab offers demonstrated medical efficacy in various Rabbit Polyclonal to HSP90A epithelial tumors (Ramakrishnan et al., 2009; Reddy et al., 2014). Based on those results, it has accomplished several approvals in Cuba including nasopharyngeal tumors, advanced head and neck carcinoma, esophageal malignancy, adult and children mind tumors and more recently pancreatic malignancy (Strumberg et al., 2012). The antibody also was authorized in 28 additional countries for treatment of some or all the above-mentioned tumors. Overexpression OTS964 of the EGFR is definitely a hallmark of HNSCC (Cohen, 2006). In several phase II medical trials, carried out in locoregionally advanced HNSCC the combination of OTS964 nimotuzumab with radiotherapy (RT) or chemo-radiotherapy (CRT) significantly improved the overall survival (OS) and objective response in comparison with the conventional therapy only (Reddy et al., 2014). In addition, a significant relationship between EGFR manifestation and OS in individuals who received nimotuzumab plus CRT or RT as well as a direct correlation between EGFR overexpression and OS has been found (Basavaraj et al., 2010). The improved survival and long-term duration of response seen in many individuals after short treatment with nimotuzumab (Bode et al., 2012; Reddy et al., 2014), suggest that obstructing EGFR signaling and inhibiting tumor cell proliferation is probably not the only mechanisms of action underlying the efficacy of this antibody. Indeed, nimotuzumabs capacity of killing tumor cells by ADCC, potentially inducing an immune response has been OTS964 speculated, however, not characterized yet. Based on the findings of cetuximab and the long-term medical responses seen with nimotuzumab, we investigated new potential mechanisms of action of this antibody that could clarify its prolonged effectiveness. Our study presents for the first time that nimotuzumab was able to destroy EGFR+ tumor cells by NK cell-mediated ADCC. As previously reported for cetuximab, nimotuzumab also induces NK-DC cross-talk, which promotes DC maturation and EGFR-specific CD8+ T-cell priming Activation of EGFR-Specific CD8+ T Cells Autologous NK and DC from HLA-A2+ donor were incubated with irradiated EGFR+ HNSCC tumor cells (PCI-15B) in the presence or not of anti-EGFR mAb (10 g/mL). After 48 h NK primed-DCs were incubated with autologous negatively isolated CD8+ T cells for 7 days at 37C with rhIL-2 (20 U/mL) and rhIL-7 (5 ng/mL). On day time 7, lymphocytes were re-stimulated with autologous DC previously primed with NK: PCI-15B (1:1:1 percentage) in the presence or not of anti-EGFR mAbs. Tradition medium (IMDM) was supplemented with IL-2 (20 U/mL) and IL-7 (5 ng/mL) as cells needed. After 7 days, CD8+ T cells were harvested and stained with CD3, CD8, zombie aqua and HLA-A2+EGFR853-861 tetramer and analyzed by circulation cytometry. Events were gated for viable (zombie aquaneg) lymphocytes, excluding doublets, that were CD3+CD8+ and analyzed the percentage of CD8+ T cells specific to HLA-A2+EGFR853-861 tetramer. HLA-A2 HIV peptide tetramer was used as bad control. Enzyme-Linked Immunosorbent Spot (ELISpot) Assay EGFR-specific T cells secreting IFN- was assessed by standard.