Ith concentrate on the evaluation of their impact on CLL immune escape. Altogether, this study will give insight into the particular immune and stromal cells involved in CLL development, with emphasis on their involvement in tumour-derived small Ev-mediated tumour immune escape. Funding: This project is funded by the Fonds National de la Recherche (FNR) INTER/DFG/16/11509946/EVRNA/Moussay. Sandrine Pierson and J e Paggetti are supported by the FNR INTER/DFG/16/11509946/EV-RNA/ Moussay. Ernesto Gargiulo is supported by the grant FNR Luxembourg PRIDE15/10675146/CANBIO.PT06.Interaction by means of exosome miRNAs between myelodysplatic cell and typical Treg Tatsuki Shibuta, Yukichi Takada and Tsukuru Umemura International University of Overall health and Welfare, Okawa City, JapanGHRH Proteins Species regulatory T cells (Treg) that have been sorted from normal peripheral blood. The exosomes were detected in cytosol of Treg by fluorescent microscopy. Microarray analysis of miRNAs in Treg intaking MDS-exosomes showed that B7-H2/ICOSLG Proteins supplier significant increases of 9 miRNAs in MDS-exosomes. The conditioned medium of MDSexosomes treated Treg culture lowered the population of activated CD4 cells (CD38 constructive cells was 39 ; handle 68). Summary/Conclusion: Our information suggested that exosomes from MDS cells affected the function of regulatory T cells through miRNA transfer. MDS exosomes might effect on immune cells to prevent the exclusion from cancer-immune program, and may be a target for the new therapies or diagnostic strategies. Funding: This work was supported in aspect by a grant from the Japan Society for the Promotion of Science (JSPS KAKENHI Grant Quantity: JP17K09020 and 17H07059).PT06.Mechanism of antitumor immunity activation by `artificial neoantigen’-presenting exosomes Yoshiyuki Koyamaa, Tomoko Itoa, Masazumi Eriguchia, Aya Hasegawab, Wakana Ouchic, Toshio Inabab and Kikuya SugiurabaIntroduction: Myelodysplastic Syndrome (MDS) is often a clonalhematopoietic disease and develops leukaemia in some situations. Therefore, MDS is a malignant hematopoietic disease and its prevalence ratio is escalating in Japan. Hematopoietic microenvironment such as bone marrow niche is actually a essential element for preserving leukaemic stem cells. To know mechanisms of interactions in between leukaemic stem cells and microenvironment is significant for the remedy of hematopoietic malignancies. Within this study, to create the new therapies and diagnostic techniques for MDS, we focused on the impact of exosomes released from MDS cells on peripheral T lymphocytes. Approaches: MDS cell line (MDS-L) was kindly offered by Kasawaki Medical University and normal peripheral blood mononuclear cells have been obtained from healthier volunteer donors. Exosomes from MDS cells had been purified by utilizing miRCURY Exosome Cell/Urine/CSF Kit and labelled by PKH67. Extracted miRNAs have been analysed by microarray method (Genopal, Mitsubishi Chemical, Japan). Cell surface antigens have been analysed by FACS Aria II and fluorescence conjugated antibodies. Outcomes: miRNA-microarray evaluation showed that nine miRNAs had been abundant in exosomes from MDS cells and had been not detected in MDS cells. Exosomes labelled with PKH67 dye have been added to liquid culture ofJapan Anti-tuberculosis Association, Shin-Yamanote Hospital, Tokyo, Japan; Osaka Prefecture University, Osaka, Japan; cOsaka Prefecture University, Tokyo, JapanbIntroduction: Tumour-derived exosomes are known to have identical antigens as the parent tumour cells, and were expected as cancer vaccines. Even so, therapy with these exosomes typically failed to elicit.