This paper reports on the use of nanoporous Pt-TiO 2 thin films coated onto magnetoelastic sensors for the detection of ethylene, an important plant growth hormone. Five different metal oxide coatings, TiO 2 , TiO 2 +ZrO 2 , TiO 2 +TTCN(1,4,7-Trithiacyclononane)+Ag, SiO 2 +Fe, and TiO 2 +Pt, each having demonstrated photocatalytic activity in response to ethylene, were investigated for their ability to change mass or elasticity in response to changing ethylene concentration. Pt-TiO 2 films were found to possess the highest sensitivities, and coupled with the magnetoelastic sensor platform capable of sensing ethylene levels of < 1 ppm.

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Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder caused by BCR-ABL fusion protein that has constitutively active tyrosine kinase activity. Although the prognosis of the patient with CML in chronic phase has markedly improved by the advent of tyrosine kinase inhibiters, the management of the patients with CML in advanced phase remains to be the major challenge. Immunotherapy is considered to be one of the promising treatment strategies for refractory CML. BCR-ABL fusion region, b3a2 peptide, represents a neo-epitope that can induce CML-specific immune responses. The activation of b3a2 peptide-specific CD4+ T helper (Th) cells and their interaction with dendritic cells (DCs) can induce a robust cytotoxic T lymphocyte (CTL)-mediated anti-leukemic immunity through epitope spreading. However, current vaccination strategies cannot effectively induce the proliferation of antigen-specific Th cells in vivo, presumably due to the tumor-induced immunosuppressive milieu. In addition, ex vivo expansion of antigen-specific Th cells attenuates their effector functions by expansion-related cell senescence, and the procedure to establish antigen-specific Th cells for each patient's treatment is too complicated for the clinical application. The purpose of the present study is to establish a method to generate large amounts of functional b3a2-specific CD4+ Th cells enough for the treatment of the patients with refractory CML by using induced pluripotent stem cell (iPSC) technology. First, we established b3a2-specific CD4+ Th clone from peripheral blood mononuclear cells of a healthy donor positive for HLA-DRB1*09:01 and HLA-A*24:02. The Th clone recognized b3a2 peptide in the context of HLA-DR9 and exhibited a Th1 profile. Second, we established iPSCs from the Th clone and differentiated them into T cell lineage by coculture with OP9 stromal cells expressing Notch ligand Delta-like 1. The iPSC-derived T cells (b3a2-iPS-T cells) expressed the same T cell antigen receptor (TCR) as the original Th clone but not CD4 molecule. Because CD4 acts as a co-receptor in the TCR-mediated Th responses, we transduced b3a2-iPS-T cells with CD4 gene. The CD4-expressing b3a2-iPS-T cells (CD4+ b3a2-iPS-T cells) recognized b3a2 peptide in the context of HLA-DR9 as the original Th clone. Moreover, CD4+ b3a2-iPS-T cells activated by b3a2 peptide induced DC maturation, as indicated by the upregulation of CD86 on DCs. In the additional presence of HLA-A24-restricted Wilms tumor 1 (WT1) peptide, the mature DCs stimulated primary expansion of WT1-specific CTLs. The CTLs exerted cytotoxicity against WT1 peptide-loaded HLA-A24 positive cell lines. These data suggest that the CD4+ b3a2-iPS-T cells have a potential to induce effective anti-leukemic immunity via DC maturation and subsequent CTL responses. The current approach enable to provide large amounts of b3a2 specific CD4+ Th-like cells that would augment CTL-mediated anti-leukemic responses via DC maturation, which may contribute to the treatment of patients with refractory CML. Disclosures Kiyoi: Yakult Honsha Co.,Ltd.: Research Funding; FUJIFILM Corporation: Patents & Royalties, Research Funding; Eisai Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Consultancy, Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Novartis Pharma K.K.: Research Funding; Mochida Pharmaceutical Co., Ltd.: Research Funding; Astellas Pharma Inc.: Consultancy, Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; FUJIFILM RI Pharma Co.,Ltd.: Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Alexion Pharmaceuticals: Research Funding; MSD K.K.: Research Funding; Japan Blood Products Organization: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Bristol-Myers Squibb: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Taisho Toyama Pharmaceutical Co., Ltd.: Research Funding; Teijin Ltd.: Research Funding. Naoe:Celgene K.K.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Toyama Chemical CO., LTD.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Patents & Royalties, Research Funding; Chugai Pharmaceutical Co., Ltd.: Patents & Royalties; FUJIFILM Corporation: Patents & Royalties, Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Astellas Pharma Inc.: Research Funding. Kaneko:AsTlym Co., Ltd: Other: founder, shareholder and scientific adviser.

3624 WT1 is a transcription factor which has been implicated in leukemogenesis and has been used as a marker of minimal residual disease (MRD). We previously demonstrated the feasibility of vaccinating AML patients in CR with a multivalent WT1 peptide vaccine and inducing immune responses. In an effort to further explore the safety and efficacy of this approach, we are conducting a Phase II study in which the vaccine is administered to AML patients in first CR and who completed all planned postremission chemotherapy. Eligible patients had WT1 transcript detectable by RT-PCR. The vaccine consisted of 4 native and derived WT1 peptides administered with the immune adjuvants Montanide and GM-CSF. Patients received 6 vaccinations over 10 weeks. Early toxicity was assessed at weeks 2 and 4. Immune responses were evaluated at week 12 by CD4+ T cell proliferation, CD3+ T cell interferon-g interferon release (ELISPOT) and WT1 peptide tetramer staining. Patients who were clinically stable and without disease recurrence could continue with up to 6 more vaccinations administered approximately every month. To date, 12 patients have been accrued to the study (6-M, 6-F; median age – 66 years, range 26–73 years). Cytogenetic subtypes varied among the study patients (Favorable-3, Intermediate-5, Unfavorable-4). The median time to vaccination after achieving CR was 7.5 months (range: 3–22 months). One patient was removed early because of relapse prior to receiving the first vaccination. Four patients have received at least 6 vaccines and 2 others have completed 12 vaccinations. Eight patients are alive without evidence of disease. One of these patients has an HLA-A02 subtype and was found to have developed T cells reactive with WT1-A (native peptide) HLA tetramers following 6 vaccinations which persisted (at a lower level) until after the 12th vaccination. Three patients relapsed during vaccination (after 1, 5 and 11 vaccines) and 2 of the 3 have died. Two of the relapsed patients who had sample available for immunologic evaluation, did not develop a CD4+ response to any of the peptides tested. Two other patients discontinued vaccination because of toxicity (hypersensitivity/pain with GM-CSF administration). Both remain in CR. No episodes of anaphylaxis or generalized urticaria were observed. Neither median disease free survival nor overall survival has been reached in this small cohort of patients. These preliminary findings demonstrate that the WT1 peptide vaccine is relatively well tolerated and has immunologic activity. Trial accrual is ongoing and further follow-up is required before any beneficial effect on outcome can be determined. Disclosures: Scheinberg: Formula Pharma: WT1 Vaccine inventor, Patent held by MSKCC and Licensed to Formula Pharma, WT1 Vaccine inventor, Patent held by MSKCC and Licensed to Formula Pharma Patents & Royalties.