Exosomes with major histocompatibility complex class II and co-stimulatory molecules are present in human BAL fluid

Abstract

Exosomes are 30-100 nm diameter vesicles formed by inward budding of endosomal compartments and are produced by several cell types, including T-cells, Bcells 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. Eur Respir J 2003; 22: 578-583.

Circulating, soluble forms of major histocompatability complex antigens are not exosome‐associated

“…It has been reported that exosomes secreted by APC contain large amounts of MHC class I (MHC-I) and II (MHC-II) molecules, as well as detectable levels of certain costimulatory molecules [8,9,12]. MHC antigens have been widely applied as a marker of APC-derived exosomes [13,14]. However, most of the above reports have utilized cell lines or cultured primary cells and the results obtained from these in vitro systems may not reflect the situation observed in vivo.…”

Cell to Cell Signalling via Exosomes Through esRNA

“…Exosomes have been identified in plasma, 13 urine, 14 malignant effusions 15 and bronchoalveolar lavage fluid. 16 It is likely that the esRNA is mediating communication in a microenvironment, but the presence of exosomes in serum may suggest that this type of genetic communication theoretically could occur also at a distance. It has been shown that mast cell derived exosomes are able to induce maturation of DCs by upregulation of MHCII, CD40, CD80 and CD86 17 or exosomes from antigen presenting cells are involved in T-cell stimulation both in vitro 18 and in vivo.…”

Exosomes as Biomarker Enriched Microvesicles: Characterization of Exosomal Proteins Derived from a Panel of Prostate Cell Lines with Distinct AR Phenotypes

“…All cells produce and release exosomes, which are often found in different body fluids such as plasma (8), serum (9, 10) malignant ascites (11,12) urine (13), amniotic fluid (14), bronchoalveolar lavage fluid (15,16), and breast milk (17,18). Recent studies suggest however that cancer cells produce exosomes, which may be differentiated from those derived from normal cells primarily based upon their cargo.…”