Nonspecific B and T Cell-Stimulatory Activity Mediated by Mast CellsIs Associated with Exosomes

• Published in: International archives of allergy and immunology Vol. 124; no. 1-3; pp. 133 - 136
• Main Authors: Skokos, Dimitris, Le Panse, Sophie, Villa, Irène, Rousselle, Jean-Claude, Peronet, Roger, Namane, Abdelkader, David, Bernard, Mécheri, Salaheddine
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2001
• Subjects: Mast Cells; Exosomes; Mast cells; Lymphocytes, B and T
• ISBN: 3805572239; 9783805572231
• ISSN: 1018-2438; 1423-0097
• DOI: 10.1159/000053691

Bone marrow-derived mouse mast cells (BMMC) and mast cell lines P815 and MC9 have recently been shown to induce antigen-independent B and T lymphocyte activation. It has been demonstrated that a physical contact between mast cells and B and T lymphocytes is not necessary since mast cell supernatants contain full activity. Electron microscopy studies revealed the presence in mast cell supernatants of small vesicles called exosomes with a heterogeneous size from 60 to 100 nm of diameter. When cocultured with spleen cells, purified exosomes induce B and T cell blast formation, proliferation as well as IL-2 and IFN-γ production. In contrast to P815 and MC9 mast cell lines, a pretreatment with IL-4 is required for BMMC to produce active exosomes. Structurally, these exosomes were found to harbor immunologically relevant molecules such as MHC class II, CD86, LFA-1 and ICAM-1. Here we provide for the first time the evidence that mast cells use exosomes as sophisticated messengers to communicate with cells of the immune system.