Sustained mucosal delivery of SAMT-247 via an intravaginal ring reduces the risk of SIVmac251 acquisition in vaccinated macaques

Résumé fourni par la source

We assess the combined effect of sustained mucosal delivery of the anti-HIV small molecule S-acyl-2-mercaptobenzamide thioester 247 (SAMT-247) via an intravaginal ring (IVR) and ΔV1DNA/ALVAC-SIV/ΔV1gp120/alum (ΔV1-SIV) immunization in female macaques. The combined approach reduces the risk of vaginal SIV mac251 infection by 82.8%, with 58% of animals remaining uninfected following 14 weekly low-dose challenges; about half of the initially protected animals also remain uninfected during a second challenge phase. Compared with a historical vaccine-only cohort, continued IVR use shows a trend toward improved protection. Protection correlates with the expansion of tolerogenic CD73 + dendritic cells, IL-10 + macrophages, IL-17-producing NKp44 + innate lymphoid cells (ILCs), and antibody-mediated natural killer (NK) cytotoxic activity targeting the V2 helical conformation. In vitro studies support ex vivo observations that SAMT-247 enhances gp120-reactive anti-inflammatory mucosal immunity and NK activity. These findings support sustained IVR-based delivery of SAMT-247 combined with V1-deleted immunogens as a promising strategy to prevent vaginal HIV transmission.