Host–pathogen dynamics: it's complicated!

This set of three review articles on host-pathogen interactions begins with a discussion of emerging concepts on homeostasis of a specific microbiome, that of the gut, and how disruption of the microbial status quo can result in several syndromes (1). The following papers highlight research on host-pathogen interactions with two oral bacteria: the dynamics between Treponema denticola virulence factors and host proteins (2); and Porphyromonas gingivalis infection of a novel animal model that will ultimately shed light on pathogenesis and innate immune responses to the organism (3).