C. T cell reactions are self-employed of exosomal MHC/peptide complexes if whole antigen is present. This establishes the prospective of using impersonalised exosomes, and will greatly increase the feasibility of developing exosome-based vaccines or restorative approaches in humans. and if an MHC mismatch on exosomes affected their function in lymphocyte activation and tumour eradication. Our results display the exosome-induced immune response is self-employed of MHC class I manifestation on exosomes when delivery of whole antigen is accomplished. We demonstrate that exosomes lacking MHC class I induce OVA-specific CD8+ T cells and IFN manifestation to the same degree as crazy type exosomes. In addition, treatment with allogeneic exosomes inside a B16 melanoma model improved T cell infiltration, OVA specific antibody levels and survival, implying the Mouse monoclonal to IgG2b/IgG2a Isotype control(FITC/PE) possibility of using allogeneic exosomes as malignancy immune treatments or vaccines. RESULTS Phenotype of B6 and MHCI?/? dendritic cell-derived exosomes First, we wanted to eliminate the probability that exosomes from MHC class I deficient (MHCI?/?) DCs display a different phenotype than their crazy type (WT) counterpart. Consequently, we compared manifestation levels of MHC class I and additional immune relevant molecules on C57Bl/6 bone marrow derived dendritic cells (BMDCs) and their exosomes from WT and MHC class I?/? mice. WT and MHC class I?/? BMDCs and their exosomes, hereafter referred to as B6 Exo-OVA and MHCI?/? Exo-OVA respectively, exhibited MHC class II (I-A/I-E), CD9, CD80, CD81, CD86, and CD40 (Number 1A, 1B) and CD11c, CD54 and CD63 (data not demonstrated) at related levels. However, CD1d manifestation was significantly reduced on MHC class I?/? BMDCs (Number ?(Figure1A)1A) but not on their related exosomes (Figure ?(Figure1B).1B). As expected, MHC class I (H2Kb) was not present on either MHC class I?/? BMDCs (Number ?(Figure1A)1A) or on their exosomes (Figure ?(Figure1B).1B). Therefore, we conclude that exosomes from MHCI?/? BMDCs have a similar set of costimulatory molecules as crazy type exosomes. Furthermore, size distribution by nanoparticle tracking analysis (NTA) shown that B6 Exo-OVA and MHCI?/? Exo-OVA experienced a diameter of 115 and 125 nm, respectively. Exosomes could potentially carry the antigen on both their surface and internally. Therefore, OVA amounts were measured both by ELISA (Number ?(Figure1D)1D) and western blot (Figure ?(Figure1E).1E). No variations in surface or internal OVA antigen levels were recognized in B6 Exo-OVA and MHCI?/? Exo-OVA. The exosome marker Alix was present at related levels in all samples (Number ?(Figure1E1E). Open in a separate windowpane Number 1 Characterization of C57Bl/6 and MHCI?/? bone marrow derived dendritic cells (BMDC) and their exosomesA. BMDC from B6 and MHCI?/? mice were analysed for surface markers by circulation cytometry after 48 h of LPS activation. B. Exosomes from B6 and MHCI?/? BMDCs were bound to anti-CD9 beads and analysed for surface markers by circulation cytometry. Data inside a) and B) are offered as MFI ratios between specific antibody and related isotype control. C. Size distribution of B6 and MHCI?/? exosomes measured by nanoparticle tracking analysis, data are demonstrated as particle concentration like a mean of three different batches’ mode sizes for the two types. For circulation cytometry data is definitely offered as mean SEM (error bars) and a non-parametric Mann-Whitney test was used, Peiminine n=4-7, * P < 0.05, ** P < 0.01, D. Surface OVA concentrations were measured by ELISA, data represents 4 self-employed batches of B6 Exo-OVA and 5 self-employed batches of MHCI?/? Exo-OVA, data represents mean SEM, E. proteins were isolated from 3 self-employed batches of B6 and MHCI?/? exosomes and the same protein amount was analysed by western blot to compare the surface and intra exosomal amount of OVA. Exosomes induce Peiminine upregulation of MHC class II expression already one hour after injection To test whether exosomes activate and target antigen showing cells Peiminine (APC) in the spleen, we injected PKH67 stained Exo-OVA/GC B6, MHCI?/? and BALB/c and analysed MHC class II manifestation on APCs in the spleen one hour after injection. Peiminine The PKH67 signal was hardly recognized, consequently only MHCII manifestation on recipient cells was analysed. DCs, inflammatory monocytes and macrophages upregulated MHCII manifestation already one hour after injection compared to a dye control (Number ?(Figure2).2). No difference in MHCII manifestation was seen on B cells. However, we have previously seen that Exo-OVA/GC induce upregulation of Peiminine CD69 on B.