Macrophage-induced reduction of bacteriophage density limits the efficacy of in vivo pulmonary phage therapy (Nature Communications)

In mouse models of acute Pseudomonas aeruginosa pneumonia, depleting alveolar macrophages shortened the survival of adult male mice without raising lung bacterial load, yet lung P. aeruginosa levels were significantly lower in macrophage-depleted than in immunocompetent mice during phage treatment. A mathematical model and experiments indicated that alveolar macrophages phagocytose therapeutic phages and reduce phage density in the lungs (Zborowsky, Weitz, Debarbieux and colleagues).