The DBL-1/TGF-β signaling pathway regulates pathogen-specific innate immune responses in C. elegans

The innate immune response coordinates several molecular activities, including a cell-cell signaling pathway called Transforming Growth Factor-β (TGF-β), conserved in species from the simplest animals to humans. In the roundworm C. elegans, the DBL-1/TGF-β pathway is required for an effective innate immune response to fight some fungal and bacterial challenges. To determine if DBL-1 is specifically required to mount an effective innate immune response against a broad range of bacteria, we challenged wild-type and dbl-1(nk3) mutant roundworms with a selected panel of bacteria that are opportunistic human pathogens. We compared avoidance behavior, nematode survival, bacterial colonization, pharyngeal pumping, and gene expression changes of wild-type and dbl- 1(nk3) animals on our bacterial panel. Loss of DBL-1 function has a strong, specific effect on some of these C. elegans innate immunity-associated traits. This work will expand our knowledge about how the DBL-1/TGF-β pathway protects animals from a variety of immune challenges.