Novel MHC class I structures on exosomes

Sarah Lynch, Susana G Santos, Elaine C Campbell, Ailish M S Nimmo, Catherine Botting, Alan Prescott, Antony N Antoniou, Simon J Powis

Research output: Contribution to journalArticlepeer-review

73 Citations (Scopus)


Exosomes are nanometer-sized vesicles released by a number of cell types including those of the immune system, and often contain numerous immune recognition molecules including MHC molecules. We demonstrate in this study that exosomes can display a significant proportion of their MHC class I (MHC I) content in the form of disulfide-linked MHC I dimers. These MHC I dimers can be detected after release from various cell lines, human monocyte-derived dendritic cells, and can also be found in human plasma. Exosome-associated dimers exhibit novel characteristics which include 1) being composed of folded MHC I, as detected by conformational-dependent Abs, and 2) dimers forming between two different MHC I alleles. We show that dimer formation is mediated through cysteine residues located in the cytoplasmic tail domains of many MHC I molecules, and is associated with a low level of glutathione in exosomes when compared with whole cell lysates. We propose these exosomal MHC I dimers as novel structures for recognition by immune receptors.

Original languageEnglish
Pages (from-to)1884-91
Number of pages8
JournalJournal of Immunology
Issue number3
Publication statusPublished - 1 Aug 2009


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