CONICET | Buscador de Institutos y Recursos Humanos

Introduction: Triiodothyronine (T3) triggers Th1 and Th17 profiles through dendritic cell (DC) activation driving pro-inflammatoryand cytotoxic responses and restraining tolerogenic signals.Objectives: To characterize Extracellular Vesicles secreted by DCs (EV-DC) from control and T3-stimulated conditions and toassess their role in paracrine DC communication.Methods: Immature bone marrow DCs (iDC) obtained from C57BL/6 mice were stimulated (or not, control) with T3 (5nM-18h).Secreted EV-DC from control and T3-stimulated DCs (EV-DC-T3) were isolated by differential ultracentrifugation (2,000g: 2K;10,000g: 10K and 100,000g: 100K). Morphological analysis was conducted by Transmission Electron Microscopy (TEM) anddynamic light scattering (DLS), and molecular analysis by western blot (CD9 and CD81). A functional assay evaluated the syngeneicDC profile induced by EV-DC from both conditions (CD11c, MHCII and CD86 by FACS; IL-12 by FACS and ELISA). Statisticalanalysis: Dunn?s Multiple Comparisons and Mann Whitney tests.Results: TEM and DLS analysis of EV-DC did not show morphological changes in control vs EV-DC-T3 and revealed higherfrequency of EV-DC>150nm for 2K and 10K-EVs, whereas 100K exhibited more than 90% of EV-DC sized 30-150 nm. All fractionsexhibited CD9 and CD81. 10K and 100K from both control and EV-DC-T3 activated syngeneic DCs (IL-12 production). The sameeffect was induced by 2K EV-DC-T3, but not by control EV-DC.Conclusion: The study allowed the characterization of EV-DC and demonstrated their ability to induce syngeneic iDC activationwith fraction and condition dependence. Results suggest that EV-DC may be involved in the adaptive response induced by T3exposure to DCs. Further ongoing studies will enlighten this issue