PROJECT SUMMARY A vaccine is a promising approach for stopping the spread of HIV infections. Although vaccine regimens in clinical trials show various levels of protection against HIV, there is no effective vaccine available for a large population yet. Preclinical and clinical data demonstrate the importance of both adjuvants and antigens for an effective HIV vaccine. Particularly, stimulation of toll-like receptors (TLRs) or stimulator of interferon genes (STING) boosts the immune response of the HIV antigens in multiple animal models. Meanwhile, HIV immunogens are a critical factor for both humoral immunity and cell-mediated immunity such as broadly neutralizing antibodies (bnAbs) and cytotoxic T cells. Despite these important advances, significant challenges remain in immunogen design, immunogen delivery, and adjuvant choice. To overcome these challenges, we propose to integrate adjuvant derived nanoparticles and engineered mRNA for HIV vaccine discovery. In preliminary studies, we developed adjuvant derived nanoparticles (ANPs) using TLR or STING agonists, which showed great potential for efficient mRNA delivery as a vaccine platform. Moreover, we constructed glycosylated HIV immunogens that trigger mannose-binding lectin (MBL)-mediated innate immune recognition, leading to enhanced antibody responses. Additionally, we systematically investigated the untranslated regions (UTRs) of mRNAs in order to enhance protein production. Through a comprehensive analysis of endogenous gene expression and de novo design of UTRs, we identified the optimal combination of 5’ and 3’ UTR for mRNA engineering. Based on these results and findings, the goal of this proposed project is to develop adjuvant derived nanoparticles as functional nanomaterials capable of efficiently delivering HIV immunogens in vivo, consequently generating strong and durable humoral and cell-mediated immunity against HIV. The following specific aims will be carried out to accomplish our goal: 1) Synthesis and characterization of adjuvant derived nanoparticles (ANPs); 2) Engineering of mRNA transcripts encoding various HIV immunogens with high translation efficiency; and 3) Determination of immunogenicity and safety profiles of ANPs-mRNA in mouse and non-human primate models. Encouraged by results from our preliminary studies, we expect the newly designed nanomaterials from this proposal to establish a vaccine candidate, which can facilitate clinical translation and a new avenue for HIV vaccine discovery. Knowledge gained from this study can also be extended to other types of vaccines for emerging pathogens.