Defend or reproduce? Muscle-derived glutamate determines an immune-reproductive energetic tradeoff.

There are dramatic disparities in infection susceptibility within populations. In this issue of Cell Metabolism, Zhao and Karpac uncover a muscle-adipose-gut axis in Drosophila that explains variability in pathogen susceptibility. They show that the degree of intramuscular NF-κB activation accounts for differences in circulating glutamate, which enhances infection resistance at the expense of reproduction.