Herpes simplex virus 1 harboring poly(T) DNA sequences as a key ligand for AIM2 inflammasome activation and host defense

Abstract Herpes simplex virus type 1 (HSV-1) infection remains a major global health challenge, yet the mechanisms underlying strain-specific innate immune responses are poorly understood. Here, we show that distinct HSV-1 strains differentially activate the absent in melanoma 2 (AIM2) inflammasome. The HF strain robustly induces AIM2-dependent inflammasome activation, whereas the F and KOS strains elicit minimal responses despite comparable infection efficiency. We demonstrate that this difference is driven by viral genomic features rather than replication capacity. Genomic analyses identify a poly(T) DNA sequence within the UL25-UL26 intergenic region that is enriched in the HF strain. Deletion of a 14-mer poly(T) sequence markedly impairs inflammasome activation, cytokine release, and host protection in vivo, whereas introduction of a poly(T) tract into the F strain is sufficient to confer AIM2 activation and enhanced host defense. Furthermore, poly(T)-mediated AIM2 activation is length-dependent, conserved in human macrophages, and requires a cGAS-STING-IRF1 licensing axis. Together, these findings identify viral poly(T) DNA as a key determinant of strain-specific AIM2 inflammasome activation and reveal how viral genomic variation shapes innate immune recognition.