A Dendritic cell targeted vaccine induces long term HIV-specific immunity within the gastrointestinal tract

Despite significant therapeutic advances for HIV-1 infected individuals, a preventative HIV-1 vaccine remains elusive. Studies focusing on early transmission events, including the observation that there is a profound loss of gastrointestinal (GI) CD4(+) T cells during acute HIV-1 infection, highlight the importance of inducing HIV-specific immunity within the gut. Here, we report on the generation of cellular and humoral immune responses in the intestines by a mucosally administered, dendritic cell (DC) targeted vaccine. Our results show that nasally delivered α–CD205-p24 vaccine in combination with polyICLC, induced poly-functional immune responses within naso-pulmonary lymphoid sites that disseminated widely to systemic and mucosal (GI tract and the vaginal epithelium) sites. Qualitatively, while α–CD205-p24 prime-boost immunization generated CD4(+) T cell responses, heterologous prime-boost immunization with α–CD205-p24 and NYVAC gag-p24 generated high levels of HIV-specific CD4(+) and CD8(+) T cells within the GI tract. Finally, DC targeting enhanced the amplitude and longevity of vaccine induced immune responses in the GI tract. This is the first report of a nasally delivered, DC targeted vaccine to generate HIV-specific immune responses in the GI tract and will potentially inform the design of preventative approaches against HIV-1 and other mucosal infections.