Treatment of clonal hematopoiesis associated atherosclerosis via vaccine-based clearance of the mutant cells

• Tet2 -mutant macrophages in atherosclerosis develop immunogenic neoantigens . • A hydrogel vaccine delivering these neoantigens with immune boosters (GM-CSF/R848) to target mutant clones. • The vaccine selectively cleared pathogenic Tet2 -mutant cells in plaques via CD8 + T cells. • This strategy pioneers mutation-directed immunotherapy for clonal hematopoiesis-driven cardiovascular disease. Clonal hematopoiesis of indeterminate potential (CHIP), driven by somatic mutations (e.g., TET2 ), is an independent risk factor for atherosclerosis (AS). CHIP-mutant macrophages promote plaque inflammation, but targeted therapies are lacking. Crucially, whether these clones acquire immunogenic neoantigens—enabling immune clearance—remains unexplored. Objective: To investigate if Tet2 -mutant cells in CHIP-associated AS develop immunogenic neoantigens and evaluate a neoantigen-targeting vaccine strategy. Methods: Tet2 was edited in hematopoietic cells via CRISPR/Cas9 and transplanted into Ldlr -/- mice fed a high-fat diet to model CHIP-accelerated AS. DNA and RNA sequencing of Tet2 -mutant macrophages identified nonsynonymous mutations. Neoantigen immunogenicity was predicted in NetMHCpan. A therapeutic vaccine (GelVax) encapsulating mutant cell lysates (neoantigen source), GM-CSF (DC recruitment), and R848 (TLR agonist) within a biocompatible hydrogel was developed. Efficacy was assessed in the AS model. Results: Tet2 deficiency exacerbated atherosclerosis (+72% plaque area) and systemic inflammation. RNA-seq revealed 363 nonsynonymous mutations in mutant macrophages; 52 peptides showed high MHC-I binding affinity, confirming neoantigenicity. GelVax vaccination reduced aortic plaque burden by 45%, selectively cleared Tet2 -mutant macrophages in plaques, attenuated systemic cytokines (TNF-α, IL-1β), improved plaque stability (↓ necrotic core, ↑ collagen), and protection was primarily CD8 + T-cell dependent. Conclusion: Tet2 -mutant cells in CHIP-associated AS acquire immunogenic neoantigens. Leveraging these antigens via a hydrogel vaccine induces clone-specific CD8 + T cell responses, clears pathogenic macrophages, and ameliorates atherosclerosis. This validates mutant neoantigens as actionable targets for CHIP-driven cardiovascular disease