Signaling in the innate immune response

The nematode Caenorhabditis elegans relies on its innate immune defenses to counter infection.In this review, we focus on its response to infection by bacterial and fungal pathogens.We describe the different families of effector proteins that contribute to host defense, as well as the signal transduction pathways that regulate their expression.We discuss what is known of the activation of innate immunity in C. elegans, via pathogen recognition or sensing the damage provoked by infection.Damage causes a stress response; we review the role of stress signaling in host defense to infection.We examine examples of inter-tissue communication in innate immunity and end with a survey of post-transcriptional regulation of innate immune responses.This chapter will deal primarily with the signaling pathways that control innate immunity to bacterial and fungal infection in C. elegans and their integration with cellular and organismal physiology.This is an area of study that has expanded enormously since the first edition of this chapter (Signaling in the immune response), and we have been selective in the literature that we cite.The reader is referred elsewhere for various related topics not covered here: innate immunity to other pathogens, including natural viruses (