Primitive Toll signalling: bugs, flies, worms and man

A current area of interplay between immunologists, geneticists and developmental biologists concerns how Toll receptors assumed their dual roles in pathogen recognition and insect embryo patterning. The development of mechanisms that recognize and control infectious pathogens has been essential for the survival of metazoan organisms. Here, Padraic Fallon and colleagues consider the insights that might be gained from using nematodes to study immune signalling pathways.