House dust mite extract primes Drosophila melanogaster host defense against microbial infections through two distinct mechanisms

For perennial allergies, the treatment involves exposure to house dust mite (HDM) extracts that aim to block T helper 2 responses. Here, we investigate whether exposure to HDM extracts affects other aspects of innate host defenses against infection using the Drosophila genetic model organism.

We find that pre-treatment of flies with HDM extract injection provides a degree of protection against several types of microbial infections, namely Gram-negative and Gram-positive bacterial infections as well as fungal infections. Interestingly, this protection appears to be achieved through distinct mechanisms. The priming afforded by HDM extracts against Gram-negative bacteria is mediated via a mild induction of the Immune deficiency pathway.