LAUSR

Abstract The outcome of microbial infections in mammals, including humans, is affected by the age, sex, and reproductive status of the host suggesting a role for sex steroid hormones. Testosterone, estradiol, and progesterone, signaling through their respective steroid receptors, affect the functioning of immune cells to cause differential susceptibility to parasitic, bacterial, and viral infections. Microbes, including fungi, bacteria, parasites, and viruses, can also use sex steroid hormones and manipulate sex steroid receptor signaling mechanisms to increase their own survival and replication rate. The multifaceted use of sex steroid hormones by both microbes and hosts during infection forms the basis of this review. In the arms race between microbes and hosts, both hosts and microbes have evolved to utilize sex steroid hormone signaling mechanisms for survival. Graphical abstract Figure. No Caption available. HighlightsSex steroid hormone concentrations as well as susceptibility to microbial infections differ between the sexes and change over the life courseSex steroid hormones can alter the activity of immune cells to affect host immune responses during microbial infectionsMicrobes can alter the synthesis and metabolism of sex steroids, receptor signaling activity, and the transcription of genes containing hormone response elementsBoth hosts and microbes have evolved to utilize sex steroids for survival