Ex vivodsDNA-EVs stimulated maturation of DCs – ↑ CD40, CD80, CD86 expression and STING-dependent activation of IFN-β synthesis.In vivoTSA breast carcinoma modelProphylactic vaccination (SC)dsDNA-EVs elicited tumour-specific CD8+ T cell response that more significantly protected mice from tumour development (2/6 mice without tumours, tumours infiltrated with tumour antigen-specific CD8+ T cells) in comparison with EVs (0/6 mice without tumours). The gene discussed is CD86; the disease is breast carcinoma.