CD4 and neoplasm: Ex vivoRab27-EVs upregulated MHC II, CD80, CD86 on DCs and stimulated synthesis of IL-1β, TNF-α and RANTES by DCs.DC/Rab27-EVs significantly ↑ CD4+T cell proliferation.In vivoA549 xenograft modelRab27-EVs significantly ↓ tumour growth in both prophylactic and therapeutic settings in comparison with EVs (SC vaccination).Rab27-EVs activated Th1 immune response – splenocytes of mice vaccinated with Rab27-EVs expressed ↑ levels of IL-2 and IFN-γ.