Dictyostelium discoideum as a model to study host-pathogen interactions.

Dictyostelium discoideum is a molecularly amenable host model system for several human pathogens, including Legionella pneumophila, Mycobacterium avium, Mycobacterium marinum, Pseudomonas aeruginosa, and Cryptococcus neoformans. Dictyostelium wild-type cells have proven useful in screening and identifying numerous bacterial und fungal virulence factors. Moreover, Dictyostelium mutant cells can be used to identify genetic host determinants of susceptibility and resistance to infections. Marker genes such as the green fluorescence protein (GFP) gene allow the in vivo monitoring of infection-relevant host factors. Here, we present methods that have already contributed to the deciphering of important aspects of the Dictyostelium-Legionella interaction. Moreover, the described phagocytosis assay, infection assay, and the confocal in vivo monitoring of GFP-tagged host factors can easily be adapted to other host-pathogen interactions.