The Antibacterial Lectin RegIIIγ Promotes the... : Science (original) (raw)

The Antibacterial Lectin RegIIIγ Promotes the Spatial Segregation of Microbiota and Host in the Intestine

• Shipra Vaishnava
• Miwako Yamamoto
• Kari M. Severson
• Kelly A. Ruhn
• Xiaofei Yu
• Omry Koren
• Ruth Ley
• Edward K. Wakeland
• Lora V. Hooper

Science

334(6053):p 255-258, October 14, 2011.

| DOI: 10.1126/science.1209791

The mammalian intestine is home to ∽100 trillion bacteria that perform important metabolic functions for their hosts. The proximity of vast numbers of bacteria to host intestinal tissues raises the question of how symbiotic host-bacterial relationships are maintained without eliciting potentially harmful immune responses. Here, we show that RegIIIγ, a secreted antibacterial lectin, is essential for maintaining a ∽50-micrometer zone that physically separates the microbiota from the small intestinal epithelial surface. Loss of host-bacterial segregation in RegIII γ−/− mice was coupled to increased bacterial colonization of the intestinal epithelial surface and enhanced activation of intestinal adaptive immune responses by the microbiota. Together, our findings reveal that RegIIIγ is a fundamental immune mechanism that promotes host-bacterial mutualism by regulating the spatial relationships between microbiota and host.