Fig. 1

Characterization of 9RE7 peptide presenting Salmonella-derived outer membrane vesicle. Nanoscale flow cytometry analysis of binding efficiency between Salmonella-derived outer membrane vesicle (SOMV) and nona-arginine extended HPV E7 peptide (9RE7). 10 µg of SOMV is incubated with 1 µg FITC-conjugated E7 peptide (E7-FITC), termed SOMV-E7-FITC, or FITC-conjugated 9RE7 (9RE7-FITC) peptide, termed SOMV-9RE7-FITC, with A representative flow cytometry histogram of FITC channel and B bar graph of gMFI on peptide coated SOMV. C Dynamic light scattering particle size frequency of SOMV and 9RE7-coated SOMV (SOMV-9RE7). D Z-average size comparison of SOMV and SOMV-9RE7. E Zeta potential measurements of the surface electric charge on SOMV and SOMV-9RE7. F Flow cytometry analysis of E7-specific T cell activation by SOMV-9RE7 in vitro. SOMV, 9RE7, and SOMV-9RE7 are prepared and dialyzed with 50kD MWCO Amicon centrifugal filter before incubated with dendritic cell line overnight. Upon replacing culture medium, E7-specific T cells are added to dendritic cells for another 24 h and blocked golgi protein transport inhibitor. After collecting the cell mixture, E7-specific T cells are stained with APC-A750-conjugated anti-mouse CD8α antibody stainings before cell membrane permeation and FITC anti-mouse IFNγ antibody for flow cytometry analyses. Representative flow cytometric images show CD8α and IFNγ gating. G Bar graph summary of T cells with positive IFNγ population. *p < 0.05, ****p < 0.0001