GP120-specific exosome-targeted T cell-based vaccine capable of stimulating DC- and CD4+ T-independent CTL responses

The limitations of highly active anti-retroviral therapy (HAART) have necessitated the development of alternative therapeutics. In this study, we generated ovalbumin (OVA)-pulsed and pcDNAgp120-transfected dendritic cell (DC)-released exosomes (EXOova and EXOgp120) and ConA-stimulated C57BL/6 CD8+ T cells. OVA- and Gp120-Texo vaccines were generated from CD8+ T cells with uptake of EXOova and EXOgp120, respectively. We demonstrate that OVA-Texo stimulates in vitro and in vivo OVA-specific CD4+ and CD8+ cytotoxic T lymphocyte (CTL) responses leading to long-term immunity against OVA-expressing BL6-10OVA melanoma. Interestingly, CD8+ T cell responses are DC and CD4+ T cell independent. Importantly, Gp120-Texo also stimulates Gp120-specific CTL responses and long-term immunity against Gp120-expressing B16 melanoma. Therefore, this novel HIV-1-specific EXO-targeted Gp120-Texo vaccine may be useful in induction of efficient CTL responses in AIDS patients with DC dysfunction and CD4+ T cell deficiency.