Purine salvage enzymes are innate immune regulators in Caenorhabditis briggsae and Caenorhabditis remanei.

In Caenorhabditis elegans , disruption of the purine salvage enzymes ADAH-1 or PNP-1 induces an innate immune program coined the Intracellular Pathogen Response (IPR). To determine if these enzymes have conserved immune regulatory roles, we utilized RNAi-competent strains of Caenorhabditis briggsae and Caenorhabditis remanei to knock down Cbr/ Cre-adah-1 and Cbr/ Cre-pnp-1 . In both species, knockdown of these enzymes induces expression of Cbr/Cre-pals genes, a hallmark of the C. elegans IPR. Furthermore, knockdown of Cbr- adah-1 or Cbr- pnp-1 promotes resistance to the microsporidia species Nematocida parisii . Our results suggest that perturbations to purine salvage metabolism may activate innate immune programs across Caenorhabditis species.