Extended Data Fig. 2: IgG binding to XMVs increases DC uptake.
Mouse subcutaneous tissue homogenate was prepared and centrifuged to remove cells. The supernatant was collected and exploited to treat XMVs (30 min, 37 °C). After that, the XMVs were collected by centrifugation and washed with PBS. a, A representative TEM image of XMV after stained with an anti-IgG antibody-conjugated to gold bead. Scare bar, 50 nm. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to identify and quantify the components of the protein corona. Classifications of components of the proteins (b) and their isoelectric point (pI) (c) of the top 21 abundant proteins. d, Gating strategies for analyzing antibody binding to XMVs. e, The binding of IgG, IgA, or IgM to XMVs after XMVs were incubated with subcutaneous tissue homogenate, analyzed using a CytoFLEX nanoflow cytometry. f, XMVs from different cell lines (PED, Vero) were used to prepare XMV-Ag. Mouse IgG was mixed with XMV-Ag for 30 min to form IgG-XMV-Ag. Various XMV-Ag, AUV-Ag (AUVs were derived from mouse RBC cells), or Lip- Ag were used to treat DC2.4 cells. After 2 h, The uptake of the antigen peptide by DC2.4 were determined using flow cytometry. g, XMV-Ag were preincubated with different amounts of IgG and then were added to DC2.4 cells. After 2 h, MFI of DC2.4 cells were determined using flow cytometry. h, XMV-Ag or XMV-Ag with IgG-preincubation were used to treat DC2.4 cells in the absence or present of FcR blockade. i, BMDCs were incubated with the XMV-Ag for 24 h and the presentation of SIINFEKL peptide on DC surface were stained using a H-2 K(b) OVA (SIINFEKL) antibody. After that, the cells were observed using a confocal microscopy. Green, Ag/MHC-I; blue, nuclei. Data are presented as mean ±s.d. and statistical differences in f were determined using one-way ANOVA with Tukey’s test for multiple comparison.
