The aim of this study was to investigate PD-L1 expression and its association with prognosis in esophageal squamous cell carcinoma (ESCC) before and after neoadjuvant chemotherapy (5-fluorouracil and cisplatin, NAC-FP). Using a database of 69 ESCC patients, we analyzed PD-L1 expression on tumor cells (TCs) and immune cells (ICs), as well as the density of CD8+ tumor-infiltrating lymphocytes (TILs) in pretreatment biopsy specimens-versus-surgical specimens after resection. We determined the prognostic significance of these factors. The fraction of ESCC containing ICs expressing PD-L1 and having a high CD8+ TIL density was significantly increased after neoadjuvant treatment. However, PD-L1 expression on TCs or ICs, and CD8+ TIL density, was not significantly associated with patient survival in ESCC patients. NAC-FP induced PD-L1 expression on ICs and CD8+ TILs in ESCC patients. This finding suggests that PD-1/PD-L1 blockade could be combined with NAC-FP to treat ESCC patients.

Regulatory T cells (Tregs) play an important role in immunological self-tolerance and protect the host from autoimmune disease. However, in cancer immunity, Tregs might block anti-tumor immune responses. Therefore, the depletion of Tregs using a specific agent that suppresses its function or population, such as an anti-CD25 antibody, could promote anti-tumor immune responses. In the present study, a cytotoxicity assay, enzyme-linked immunosorbent spot (ELISPOT) assay and measuring cytokine secretion, were used to study the efficacy of Treg depletion by anti-CD25 antibody added to a dendritic cell/tumor cell (DC/TC) fusion hybrid vaccine in a murine pancreatic cancer model. All the mice treated with the combined therapy of fusion hybrid vaccine and Treg depletion rejected tumor growth in a challenging test, although the rejection rate was 20% both for mice that received the fusion hybrids alone or Treg depletion alone. In addition, combined therapy showed a significantly improved survival in comparison to other treatment or control groups. The NK cell activity for DC/TC fusion + Treg depletion was significantly higher than that for the other treatment groups. Cytotoxic T lymphocyte (CTL) activity for DC/TC could potentially be enhanced by the addition of Treg depletion therapy. The treatments including DC/TC fusion induced IFN-γ secreting effector cells in ELISPOT assays. Furthermore, a cytometric beads array assay used to measure cytokine secretion showed that DC/TC fusion + Treg depletion stimulated the highest levels of IFN-γ Th1/Th2 ratios and Th17. These results demonstrate that Treg depletion combined with DC/TC fusion hybrid vaccine enhanced the efficacy of immunotherapy in pancreatic cancer by activating CTLs and NK cells.

Dehydrated hydroxyapatite (HAp), OH⁻ ion-defect induced hydroxyapatite, was prepared for dielectric measurements. We evaluated the dielectric properties of HAp in 100–500 °C, and found dielectric relaxations of two kinds. At lower temperature, relaxation that was attributed to the reorientations of OH⁻ ions was observed, where the relaxation strengths were influenced strongly by the OH⁻ concentrations. The activation energy of the OH⁻ reorientation, which was unaffected by the OH⁻ concentrations, was ascertained as 0.62–0.63 eV. However, in a higher temperature range, relaxations that had larger relaxation strength were observed and were regarded as originating from the displacement of OH⁻ ions and O²⁻ ions. The activation energies of the larger relaxation, which were affected by the OH⁻ concentrations, were ascertained as 0.73 eV and 0.81 eV. Those values are comparable to the activation energy of proton conduction, implying that the proton conduction in HAp starts at a low temperature.