Innate Immunity in C. elegans

Convergent genetic investigations in Drosophila and mice established that key signaling pathways of mammalian innate immunity are conserved in the immune responses of invertebrate organisms. We have established that C. elegans also responds to infection with pathogenic bacteria with the activation of a conserved p38 mitogen-activated protein kinase pathway, which regulates the expression of secreted immune effectors such as C-type lectins and antimicrobial peptides. We and others have established that the p38 MAPK pathway functions downstream of a conserved Toll-Interleukin-1 Receptor (TIR) domain protein, TIR-1. Recently, we defined a conserved CREB/ATF transcription factor, ATF-7, as playing a pivotal role in the activation of the C. elegans immune response. We anticipate that the ongoing investigation of innate immunity in C. elegans will reveal ancient features of host defense that may illuminate basic mechanisms of innate immunity in evolutionarily diverse species.