Nature biotechnologyAug 20, 2026

Stronger cancer-fighting response from mRNA vaccines using delayed activation of an immune system trigger

mRNA Technology Weekly Brief ↗PubMed ↗DOI ↗

Updated Aug 22, 2026

Abstract

The Syn-STING vaccine shows significant promise by eliciting robust adaptive responses and Th1-biased T cell immunity.

Synchronized STING (Syn-STING) utilizes a lipid nanoparticle to deliver multiple components, including antigen mRNA and a delayed-release STING activator.
Localized activation of STING occurs while avoiding recognition by the human STING system, as facilitated by a biodegradable linker.
In humanized STING mouse models, the vaccine demonstrates effective internalization by myeloid cells, preserving the fidelity of antigen expression.
The vaccine is associated with enhanced adaptive immune responses and reduced tumor growth.
Survival rates are prolonged with negligible anti-STING immunity observed.

Simplified

The development of cGAS-STING (stimulator of interferon genes) agonists as mRNA vaccine adjuvants has been hampered by widespread STING expression and by the observation that codelivered STING agonists suppress antigen mRNA translation. Here, to address these challenges, we engineer synchronized STING (Syn-STING): a lipid nanoparticle (LNP) codelivering antigen mRNA, mRNA encoding full-length STING transmembrane protein and a bioorthogonal-like delayed-release STING activator, DMXAA. DMXAA release is controlled by a biodegradable linker, enabling localized mouse STING activation while avoiding systemic endogeneous human STING recognition. In humanized STING mouse models, we test human papillomavirus E7 and ovalbumin antigens with mouse STING or a human STING mutant engineered for DMXAA specificity. Intratumoral or subcutaneous LNPs are preferentially internalized by myeloid cells, preserving antigen expression fidelity, achieving localized STING activation in antigen-presenting cells and preventing systemic regulatory B cell differentiation and immunocyte apoptosis. The Syn-STING vaccine elicits robust adaptive responses and Th1-biased T cell immunity. It suppresses tumor growth and prolongs survival while exhibiting negligible anti-STING immunity.