Protection from HIV and SIV requires mucosal immunity. We have developed unconventional and safe vaccines based on the delivery of SIV antigens via heat shock protein-chaperone gp96 or by HPV pseudovirion particles. We have already established that the two vaccines generate powerful vaginal and rectal immune responses that are polyepitope specific and multifunctional and generate antigen specific antibody and T cell responses, including CD8 CTL. We hypothesize and will determine that the vaccines will modify the response to vaginal SIV challenge with the effect of protecting macaques from SIV disease. We further hypothesize that by analyzing simultaneously (i) mucosal barrier function of the cervicovaginal mucus, (ii) innate and (iii) adaptive immune responses in vagina/cervix, (iv) gene expression profiles, proteomic (v) phosphoproteins and (vi) plasma membrane proteins, we will be able with the tools of systems biology identify transcriptional and signaling pathways that correlate with protection from vaginal SIV challenge. Finally, since the two vaccine approaches are distinct molecularly and mechanistically, we hypothesize that they will be synergistic if combined in a prime boost strategy and additionally combined with gp120 protein and adjuvant. This will be determined. While we are optimistic that the vaccines singly or in combination will be protective against vaginal SIV challenge, our studies also will provide the information how to further improve our vaccine approach, if even stronger protection is required.
We have developed two novel SIV vaccines that have been shown to induce immune responses in rectal and vaginal mucosa. We now will determine how these vaccines alter the response to vaginal SIV challenge and determine which component of the vaccine induced response is critical for protection. This knowledge will help to further improve the vaccines should that be necessary.
