Two studies in the mid-1990s cracked a mystery of innate immunity–how foreign invaders are recognized. One study found that signaling through Toll-like receptor 4 activated the immune response. Another identified the signal: lipopolysaccharide (LPS), a cell envelope component of Gram-negative bacteria. The discoveries brought full circle observations that began with starfish in the 1880s.
- Robert L Modlin
- Genhong Cheng
