Terutsugu Koya

Safety and tolerability of allogeneic dendritic cell vaccination with induction of Wilms tumor 1-specific T cells in a pediatric donor and pediatric patient with relapsed leukemia: A case report and review of the literature

A 15-year-old girl with acute lymphoblastic leukemia received allogeneic dendritic cell vaccination, pulsed with Wilms tumor 1 (WT1) peptide, after her third hematopoietic stem cell transplantation (HSCT). The vaccines were generated from the third HSCT donor, who was her younger sister, age 12 years. The patient received 14 vaccines and had no graft-versus-host disease or systemic adverse effect, aside from grade 2 skin reaction at the injection site. WT1-specific immune responses were detected after vaccination by both WT1-tetramer analysis and enzyme-linked immunosorbent spot assay. This strategy may be safe, tolerable and even feasible for patients with a relapse after HSCT.

Dendritic Cell-Based Adjuvant Vaccination Targeting Wilms' Tumor 1 in Patients with Advanced Colorectal Cancer

Despite significant recent advances in the development of immune checkpoint inhibitors, the treatment of advanced colorectal cancer involving metastasis to distant organs remains challenging. We conducted a phase I study to investigate the safety and immunogenicity of Wilms’ tumor (WT1) class I/II peptides-pulsed dendritic cell DC vaccination for patients with advanced colorectal cancer. Standard treatment comprising surgical resection and chemotherapy was followed by one course of seven biweekly administrations of 1–2 × 107 DCs with 1–2 KE of OK-432 (streptococcal preparation) in three patients. Clinical efficacy was confirmed based on WT1 expression using immunohistochemistry on paraffin-embedded tissues and immune monitoring using tetramer analysis and enzyme-linked immunosorbent spot (ELISPOT) assays. WT1 expression with human leukocyte antigen (HLA)-class I molecules was detected in surgical resected tissues. Adverse reactions to DC vaccinations were tolerable under an adjuvant setting. WT1-specific cytotoxic T cells were detected by both modified WT1-peptide/HLA-A*24:02 tetramer analysis and/or interferon-γ-producing cells through the use of ELISPOT assays after the first DC vaccination. Immunity acquired from DC vaccination persisted for two years with prolonged disease-free and overall survival. The present study indicated that DC vaccination targeting WT1 demonstrated the safety and immunogenicity as an adjuvant therapy in patients with resectable advanced colorectal cancer.

An update on Dendritic Cell-Based Cancer Immunotherapy

Although treating advanced cancers that affect organs with distant metastasis remains challenging, the pace of recent advances has accelerated; these advances have particularly focused on the inhibitors of key immune potentiates. Research on therapeutic vaccination involving active dendritic cell (DC)-based immunotherapy is also being performed for the induction of an effi cient immune response against cancer-associated antigens by the acquired immune system. Cancer vaccines prepared with autologous monocyte-derived mature DCs have been generated using granulocyte–macrophage colony-stimulating factor and interleukin-4, which are principally attributed to the presence of tumor-associated antigens. Wilms’ tumor 1 (WT1) is an attractive target antigen that is widely detected in many cancers. DC-based immunotherapy targeting WT1 may elicit a strong therapeutic response to cancers. DC vaccines primed with HLA class I/II-restricted WT1 peptides (WT1-DC) are a feasible option for patients with advanced cancers. Immune response monitoring using tetramer analysis and/or enzyme-linked immunosorbent spot assay has been applied to determine the effi cacy of WT1-DC. The inhibition of immune suppressors and acceleration of anti-cancer immunity with WT1-DC may comprise a promising future therapeutic strategy for treating advanced cancers.

Quality Verification of Dendritic Cell-Based Cancer Vaccine

In the era of personalized cancer therapy, immunotherapy is now emerging as a potential option. Therapeutic cancer vaccination has been developed for the induction of an efficient immune response targeting tumor-associated antigens. The efficacy of dendritic cell (DC)-based vaccines is attributed to their ability to induce immunity against cancers. Criteria for the approval of therapeutically active DCs, such as their viability and purity, are here verified based on phenotypic characteristics, linked to their antigen-presenting ability and functional analyses of phagocytosis and pinocytosis. A standardized phenotype of DCs harboring bioactive functions would be useful to provide personalized vaccines for cancer immunotherapy.

Induction of Antigen-Specific Cytotoxic T Lymphocytes by Chemoradiotherapyin Patients Receiving Wilmsâ Tumor 1-Targetted Dendritic Cell Vaccinations forPancreatic Cancer

Despite recent advances in cancer treatment, the prognosis of pancreatic cancer (PC) remains poor. Dendritic cells (DCs) play a central role in acquired immunity; therapeutic DC vaccinations have recently been developed for advanced PC. Here we present two cases of PC: inoperable PC localized to the pancreatic head (Case 1, stage IV) and local recurrence complicated by distant metastases following resection of the pancreas body and tail (Case 2, stage III). Both patients received DC vaccinations pulsed with human leukocyte antigen (HLA)-Class I/II-restricted Wilms’ tumor 1 (WT1) peptides during chemoradiotherapy. The induction of WT1 antigen-specific cytotoxic T cells (WT1-CTL) was markedly increased by chemoradiotherapy and was confirmed by measurement of WT1 tetramers and enzyme-linked immunosorbent spot (ELISpot) in both cases. WT1-CTL was found to persist at 1 year without additional DC vaccines in Case 1. In cases 1 and 2, the overall survival (OS) was 32.1 and 24.7 months, respectively, and progression-free survival (PFS) was 25.2 and 8.7 months, respectively. Adverse reactions due to the DC vaccination were tolerable even during chemoradiotherapy, resulting in disease stability. The findings of the present cases may form treatment strategies involving DC vaccination for PC.

Enzyme-Linked Immunosorbent Spot Assay for the Detection of Wilms’ Tumor 1-Specific T Cells Induced by Dendritic Cell Vaccination

Background: Despite recent advances in cancer immunotherapy and the development of various assays for T cell assessment, a lack of universal standards within immune monitoring remains. The objective of this study was to evaluate the enzyme-linked immunosorbent spot (ELISpot) assay in comparison with major histocompatibility complex-tetramer analysis in the context of dendritic cell (DC)-based cancer immunotherapy. Methods: The ELISpot assay was performed on peripheral blood mononuclear cells to assess reproducibility, daily precision, and linearity using HLA-A*24:02-restricted Cytomegalovirus peptide. Wilms’ tumor 1 (WT1) antigen-specific cytotoxic T cells were then evaluated by both the ELISpot assay and WT1 tetramer analysis in peripheral blood from 46 cancer patients who received DC vaccinations pulsed with human leukocyte antigen (HLA)-A*24:02-restricted modified WT1 peptides. Results: The ELISpot assay was proven to have reproducibility (coefficient of variation (CV) ranged from 7.4% to 16.3%), daily precision (CV ranged from 5.0% to 17.3%), and linearity (r = 0.96–0.98). WT1-specific immune responses were detected by the ELISpot assay in 34 out of 46 patients (73.9%) post-vaccination. A Spearman’s rank-correlation coefficient of 0.82 between the ELISpot assay and WT1 tetramer analysis was obtained. Conclusion: This is the first report of a comparison of an ELISpot assay and tetramer analysis in the context of dendritic cell (DC)-based cancer immunotherapy. The ELISpot assay has reproducibility, linearity, and excellent correlation with the WT1 tetramer analysis. These findings suggest that the validated ELISpot assay is useful to monitor the acquired immunity by DC vaccination targeting WT1.

Standard WT1 Expression Using Immunohistochemistry

Although it remains difficult to treat advanced cancers affecting organs with distant metastasis, therapeutic cancer vaccination is conducted for the induction of an efficient immune response against tumor-associated antigens. Wilms’ tumor 1 (WT1) shown to be the most potent tumor-associated antigens may have potentially strong therapeutic activity against cancers. WT1 expression using immunohistochemistry (IHC) can be evaluated on paraffin-embedded tissues and is proportional to mRNA levels. The standardized IHC would be useful for personalized cancer immunotherapy.

Interferon-α-inducible Dendritic Cells Matured with OK-432 Exhibit TRAIL and Fas Ligand Pathway-mediated Killer Activity

Active human dendritic cells (DCs), which efficiently induce immune responses through their functions as antigen-presenting cells, exhibit direct anti-tumour killing activity in response to some pathogens and cytokines. These antigen-presenting and tumour killing abilities may provide a breakthrough in cancer immunotherapy. However, the mechanisms underlying this killer DC activity have not been fully proven, despite the establishment of interferon-α (IFN-α)-generated killer DCs (IFN-DCs). Here mature IFN-DCs (mIFN-DCs), generated from IFN-DCs primed with OK-432 (streptococcal preparation), exhibited elevated expression of CD86 and human leukocyte antigen-DR (minimum criteria for DC vaccine clinical trials) as well as antigen-presenting abilities comparable with those of mature IL-4-DCs (mIL-4-DCs). Interestingly, the killing activity of mIFN-DCs, which correlated with the expression of CD56 (natural killer cell marker) and was activated via the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas ligand pathway, was stronger than that of IFN-DCs and remarkably stronger than that of mIL-4-DCs. Therefore, mIFN-DCs exhibit great potential as an anti-cancer vaccine that would promote both acquired immunity and direct tumour killing.