TY - JOUR T1 - Exosomes with major histocompatibility complex class II and co-stimulatory molecules are present in human BAL fluid JF - European Respiratory Journal JO - Eur Respir J SP - 578 LP - 583 DO - 10.1183/09031936.03.00041703 VL - 22 IS - 4 AU - C. Admyre AU - J. Grunewald AU - J. Thyberg AU - S. Gripenbäck AU - G. Tornling AU - A. Eklund AU - A. Scheynius AU - S. Gabrielsson Y1 - 2003/10/01 UR - http://erj.ersjournals.com/content/22/4/578.abstract N2 - Exosomes are 30–100 nm diameter vesicles formed by inward budding of endosomal compartments and are produced by several cell types, including T‐cells, B‐cells and dendritic cells (DC)s. Exosomes from DCs express major histocompatibility complexes (MHC) class I and II, and co-stimulatory molecules on their surface, and can induce antigen-specific activation of T‐cells. The aims of the present study were to investigate for the presence of exosomes in bronchoalveolar lavage fluid (BALF) from healthy individuals, and to establish if these exosomes bear MHC and co-stimulatory molecules. The authors analysed BALF taken from seven healthy volunteers and used exosomes from monocyte-derived DC (MDDC) cultures as a reference. After ultracentrifugation, exosomes were bound to anti‐MHC class II coated magnetic beads and analysed by flow cytometry and electron microscopy. The authors report for the first time that exosomes are present in BALF. These exosomes are similar to MDDC derived exosomes as they express MHC class I and II, CD54, CD63 and the co-stimulatory molecule CD86. The results demonstrate that exosomes are present in the lung, and since they contain both major histocompatibility complex and co-stimulatory molecules it is likely that they are derived from antigen presenting cells and might have a regulatory role in local immune defence. This work was supported by the Swedish Research Council (grants no. 16x-7924, 74x-14182, and 6537), the Swedish Council for Work Life Sciences, the Swedish Asthma and Allergy Association's Research Foundation, the Hesselman Foundation, Konsul TH Bergs Foundation, the Swedish Heart‐Lung Foundation, the Vårdal Foundation, the Centre for Allergy Research at Karolinska Institutet, the King Oscar II Jubilee Foundation, the King Gustaf V 80th Birthday Fund and the Karolinska Institutet. ER -