Ancient bacterial defenses underpin many human antiviral mechanisms

A new review shows that core components of human antiviral immunity, such as cGAS-STING, inflammasomes, argonautes and viperin, originated in bacteria billions of years ago.

Defence against viruses is a universal trait of cellular life, ranging from solitary bacteria to humans. Recent research reveals that many elements of the human antiviral arsenal—cGAS-STING signaling, inflammasome complexes, argonaute proteins and the enzyme viperin—have direct counterparts in bacterial anti-phage systems that emerged billions of years ago. This review integrates data from comparative genomics, structural biology and functional studies to define common principles of pathogen sensing, signal propagation and effector execution across kingdoms.

It demonstrates that bacterial pattern-recognition receptors and CRISPR-based immunity correspond to human toll-like receptors and interferon-stimulated genes, establishing a unified framework for host-virus battles. The authors discuss how these ancient pathways have been repurposed in multicellular organisms and identify gaps in our understanding of their regulation and evolution. Funding acknowledgments note support from the Pew Biomedical Scholars programme, Burroughs Wellcome Fund, The Mathers Foundation, Cancer Research Institute, Parker Institute for Cancer Immunotherapy, Gates Foundation and the NIH.