In vivoB16-OVA melanoma modelProphylactic settingsCD8+ T cell response was induced in mice immunized (IV) with OVA-EVs (but not with SIINFEKL-EVs).CTL response activated with OVA-EVs was totally dependent on CD4+ T cells and additionally on B cells (full OVA protein contains both Th and B cell epitopes).OVA-EVs were superior in protecting mice against B16-OVA melanoma growth in comparison with SIINFEKL-EVs. The gene discussed is CD4; the disease is melanoma.