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- Rayner, S, et al.
(författare)
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Identification of small RNAs in extracellular vesicles from the commensal yeast Malassezia sympodialis
- 2017
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7, s. 39742-
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Tidskriftsartikel (refereegranskat)abstract
- Malassezia is the dominant fungus in the human skin mycobiome and is associated with common skin disorders including atopic eczema (AE)/dermatitis. Recently, it was found that Malassezia sympodialis secretes nanosized exosome-like vesicles, designated MalaEx, that carry allergens and can induce inflammatory cytokine responses. Extracellular vesicles from different cell-types including fungi have been found to deliver functional RNAs to recipient cells. In this study we assessed the presence of small RNAs in MalaEx and addressed if the levels of these RNAs differ when M. sympodialis is cultured at normal human skin pH versus the elevated pH present on the skin of patients with AE. The total number and the protein concentration of the released MalaEx harvested after 48 h culture did not differ significantly between the two pH conditions nor did the size of the vesicles. From small RNA sequence data, we identified a set of reads with well-defined start and stop positions, in a length range of 16 to 22 nucleotides consistently present in the MalaEx. The levels of small RNAs were not significantly differentially expressed between the two different pH conditions indicating that they are not influenced by the elevated pH level observed on the AE skin.
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- Vallhov, H, et al.
(författare)
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Exosomes containing glycoprotein 350 released by EBV-transformed B cells selectively target B cells through CD21 and block EBV infection in vitro
- 2011
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 186:1, s. 73-82
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Tidskriftsartikel (refereegranskat)abstract
- Exosomes are nano-sized membrane vesicles released from a wide variety of cells, formed in endosomes by inward budding of the endosomal limiting membrane. They have immune stimulatory-, inhibitory-, or tolerance-inducing effects, depending on their cellular origin, which is why they are investigated for use in vaccine and immune therapeutic strategies. In this study, we explored whether exosomes of different origins and functions can selectively target different immune cells in human peripheral blood. Flow cytometry, confocal laser scanning microscopy, and multispectral imaging flow cytometry (ImageStream) revealed that exosomes derived from human monocyte-derived dendritic cells and breast milk preferably associated with monocytes. In contrast, exosomes from an EBV-transformed B cell line (LCL1) preferentially targeted B cells. This was not observed for an EBV− B cell line (BJAB). Electron microscopy, size-distribution analysis (NanoSight), and a cord blood transformation assay excluded the presence of virions in our LCL1 exosome preparations. The interaction between LCL1-derived exosomes and peripheral blood B cells could be blocked efficiently by anti-CD21 or anti-gp350, indicating an interaction between CD21 on B cells and the EBV glycoprotein gp350 on exosomes. The targeting of LCL1-derived exosomes through gp350–CD21 interaction strongly inhibited EBV infection in B cells isolated from umbilical cord blood, suggesting a protective role for exosomes in regulating EBV infection. Our finding also suggests that exosome-based vaccines can be engineered for specific B cell targeting by inducing gp350 expression.
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- Vallhov, H., et al.
(författare)
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The effect of gold nanoparticles on dendritic cells
- 2006
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Ingår i: 2006 NSTI Nanotechnology Conference and Trade Show. - 0976798565 - 9780976798569
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Konferensbidrag (refereegranskat)abstract
- Gold is recognized as one of the most biocompatible and stable materials, and has been used for many years as a medical agent, among others in the form of salt for the treatment of rheumatoid arthritis [1]. More recent biological applications have been focusing on using gold nanoparticles for drug and gene delivery [2], or as a photothermal agent causing highly localized heating applicable in cancer therapy [3]. There is however very little information available concerning what influence such particles have on the immune system, e.g. on dendritic cells (DCs). DCs are present throughout the human body but are particularly localized at antigen-exposed sites, such as the skin. They are the most efficient type of antigen presenting cells having a capacity both to initiate primary and secondary immune responses, by expressing cytokines, MHC and co-stimulatory molecules such as CD80, CD83 and CD86 [4-5]. DCs decide whether an immune response should be initiated and are able to affect the development of T-helper cells into Treg-, Th1- or Th2-cells depending on their cytokines produced and their expression of co-stimulatory molecules [6]. We addressed the question whether spherical gold nanoparticles of 6 nm in diameter affect DCs, looking at morphology, viability, expression of cytokines and of co-stimulatory and antigen presenting molecules. This was assessed by using human monocyte derived DCs (myeloid DCs) and peripheral blood mononuclear cells from healthy blood donors together with gold nanoparticles [7], and various techniques including light microscopy, flow cytometry and ELISpot. After having overcome aggregation problems of gold nanoparticles by stabilizing with human serum albumin (HSA) and developed methods to produce nanoparticles with low lipopolysaccharide (LPS) contamination, experiments revealed that both morphology and viability were not affected by the gold nanoparticles. The expression of CD80, CD83, CD86 and MHC class II was only to a minor degree up-regulated after 6 and 24 h, and CD40 and MHC class I was not affected, which indicates biocompatibility of gold nanoparticles. This is further supported by low or no expression of the cytokines IL-10, IL-12 and IFN-alpha. HSA by itself did not have an effect on the DCs. In conclusion, gold nanoparticles of 6 nm in diameter are highly unlikely to initiate a danger signal to the immune system through the dendritic cells, and have therefore the potential to be used as inert carriers in biomedical applications.
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