TY - JOUR T1 - LSC 2013 abstract - Functional modulation of bone marrow-derived dendritic cells depends on polystyrene particles size JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - P1565 AU - Emilie Seydoux AU - Fabian Blank AU - Alke Fink AU - Barbara Rothen-Rutishauser AU - Christophe Von Garnier Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/P1565.abstract N2 - The respiratory tract may represent an ideal target organ for immunotherapy, given a vast surface where interaction between antigen-presenting cells (APC) such as dendritic cells (DC) and novel nano-sized immunomodulatory compounds may occur. To date, immune responses to a specific size, shape or chemical surface of a given synthetic nano-sized particle are still largely unknown. To investigate the effect of size on interactions between particles and APC, bone marrow-derived DC (BMDC) were exposed in vitro to 20nm or 1000nm polystyrene (PS) particles. Changes in surface phenotype, activation, the capacity of BMDC to take up and process antigen, as well as antigen-specific stimulation of CD4+T cells, were analysed by flow cytometry and confocal microscopy. With 20nm particles we observed higher frequencies (69.1%) of particle positive BMDC already at the early (10 minutes) time-point, compared to larger 1000nm particles (35.8%, p=0.0004). PS-particles did not significantly affect surface phenotype or expression of activation markers, such as CD40, CD86 or MHCII. Though particle treatment did not alter antigen uptake, 20nm-sized particles decreased the capacity of BMDC to process antigen, without affecting the ability to stimulate antigen-specific CD4+T cells. These data showed that micro-sized (1000nm) PS particles did not significantly affect DC phenotype and function, while nano-sized (20nm) particles decreased antigen processing in DC. Therefore, particle size may represent a relevant parameter determining DC function and down-stream immune responses to particles. ER -