Send to

Choose Destination
Trends Immunol. 2014 Oct;35(10):495-502. doi: 10.1016/ Epub 2014 Aug 28.

Rethinking the role of immunity: lessons from Hydra.

Author information

Zoological Institute, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, 24098 Kiel, Germany. Electronic address:


The ability of multicellular organisms to detect and respond to microorganisms is fundamental and has ancient evolutionary origins. In this review, I evaluate our current understanding of the evolution of epithelial-based innate immunity in Hydra, an apparently simple animal that shares deep evolutionary connections with all animals, including humans. I highlight growing evidence that the innate immune system with its host-specific antimicrobial peptides and rich repertoire of pattern recognition receptors has evolved in response to the need for controlling resident beneficial microbes rather than to defend against invasive pathogens. These findings provide new insight into how developmental pathways beyond those associated with the immune system, such as stem cell transcriptional programs, interact with environmental cues such as microbes.


Cnidaria; Toll-like receptor (TLR) signaling; antimicrobial peptides; commensal microbiota; innate immunity; orphan genes

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center