PEVs loaded with native OVA process and present OVA peptide to induce antigen-specific T-cell lymphoproliferation (A) The experimental plan. NS, unpulsed. (B) Histogram showing CFSE fluorescence shift of CD3⁺CD8⁺ T-cell populations when coincubated with DCs, activated platelets (PLTs), or PEVs left unpulsed or pulsed with SIINFEKL peptide (PP) or OVA for 7 days. (C) Percentage of CD3⁺CD8⁺ lymphoproliferative cells after coincubation with DCs, PLTs, or PEVs, unpulsed or pulsed with PP or OVA for 7 days. Data are the mean ± standard error of the mean (SEM); n = 14). **P < .01; ***P < .001; ****P < .0001 vs unpulsed (Friedman test followed by Dunn’s post hoc test for multiple comparisons). NS, nonsignificant. (D) Percentage of CD3⁺CD8⁺ lymphoproliferative cells after a 7-day coincubation with PP pulsed DCs or supernatant (surn), depleted of PEVs by ultracentrifugation, left unpulsed or pulsed with PP or OVA. Data are the mean ± SEM (n = 5). **P < .01 vs unpulsed (Mann-Whitney). (E) Proportion of CD3⁺CD8⁺ lymphoproliferative cells after a 7-day coincubation with OVA-pulsed PEVs, treated or not with epoxomicin (epoxo) for 2 hours, and PP-pulsed DCs (DC+PP), treated or not with epoxomicin (epoxo). Dashed lines are unstimulated conditions. Data are the mean ± SEM (n = 9 for PEVs and n = 3 for DC). **P < .01 (Wilcoxon). NS, nonsignificant.