Engineered T cells that express chimeric antigen receptors (CARs) have shown remarkable efficacy against hematological malignancies. However, broad implementation of CAR T cell therapies is limited by the lengthy (3–5 weeks) and costly ($350K–450K per treatment) ex vivo manufacturing pipeline. This proposal seeks to develop antigen-presenting nanoparticles (APNs) for in situ programming of virus-specific T cells for rapid and cost-efficient CAR T cell manufacturing. Virus-specific T cells present a promising opportunity to enhance CAR T cell therapy, as they have improved persistence and proliferation potential, and allow for viral vaccination to augment CAR therapy through their endogenous receptors. This proposal will focus on influenza A virus (IAV)- specific T cells to exploit the existing seasonal influenza vaccination to boost CAR activities. To deliver CAR to IAV-specific T cells, APNs will comprise lipid nanoparticles (LNPs) that encapsulate CAR-encoded mRNA and are decorated with HLA-A peptide-major histocompatibility complex (pMHC) displaying influenza peptide epitopes. This proposal will use APNs to deliver human B-cell maturation antigen (BCMA) CAR in the context of multiple myeloma with future goals to expand to other CAR specificities and indications, including CD19 positive cancers. The goal in Aim 1 is to develop APNs for transfection of human influenza-specific T cells with αBCMA CAR in vivo, and characterize the CAR transfection specificity in the target IAV-specific T cells versus other major cell populations. Aim 2 will be focused on validating the anti-cancer efficacy of αBCMA CAR T cells after in situ transfection using a mouse model recapitulating human multiple myeloma. The vaccination strategy to expand IAV-specific T cells and to boost their effector functions will be tested using inactivated influenza virions to vaccinate the CAR-expressing, IAV-specific T cells and compare the resulting anti-cancer potency with the unvaccinated cohort. In Aim 3, CRISPR/Cas9 will be implemented with APNs for in vivo gene editing of T cells with CAR for durable CAR expression and enhanced anti-cancer potency by delaying T-cell differentiation and exhaustion. The success of this proposal will challenge existing paradigms of T cell engineering, reduce the cost of CAR T cell therapy, and enhance anti-cancer activity through influenza vaccination to ultimately democratize CAR T cells for cancer therapy. Through this work, the candidate will close the knowledge gaps by the mentorship of an exceptional advisory committee: (1) Gabe Kwong, Ph.D. (CAR T cell engineering), (2) Phil Santangelo, Ph.D. (mRNA therapeutics and CRISPR/Cas), (3) Rafi Ahmed, Ph.D. (anti-viral T cell immunity and memory/exhaustion T cell biology), and (4) Madhav Dhodapkar, M.D. (hematology/oncology and myeloma cancer models). This strong mentoring team and the abundant resources provided by Georgia Tech and Emory University constitute a fertile mentoring environment for at...