Mount Sinai researchers reported a design principle for mRNA vaccine potency: detargeting mRNA expression away from hepatocytes can strengthen T-cell immunity in a lymphoma model. The work, published in Nature Biotechnology, uses microRNA-based technology to selectively silence mRNA expression in specific cell types. The study challenged a long-held assumption that strong T-cell priming depends on directing mRNA to dendritic cells. Instead, dendritic-cell silencing did not impair priming, while hepatocyte detargeting boosted immune responses in preclinical settings. The results shift how developers may think about tissue targeting in mRNA platforms, particularly for systemic administration where hepatocyte uptake can be substantial and may act to dampen immunity.