Brothers in arms
Key human defenses against pathogens were forged billions of years ago in microbial battles with viruses
21 May 2026
2:00 PM ET
By Richard Stone
Ancient wars between microbes gave us key immune defenses
A better understanding of battles between bacteria and viruses could inspire new medicines
TL;DRAI
Core human innate immune proteins trace to 3-billion-year-old bacterial antiphage systems; 300+ microbial defenses are now mapped, 12+ sharing molecular parts with humans. The discovery points to more precise antiviral drug targets and a molecular toolkit expansion on CRISPR's scale.
4,271 words~19 min read
