When viruses abound in your population, it’s good to be a bat! An alarming number of highly lethal viral diseases circulate in bats of diverse species. The secret for bats is that their immune systems have limited inflammatory responses. That contrasts with human immune systems impacted by COVID, Ebola, Marburg, and other diseases. The really deep damage done to us humans by these diseases stems from inflammation.
Ariadna Morales in Frankfurt and 33 colleagues in 9 nations compared genes in 115 species of mammals, to see why bats are special. They looked for genes that were being strongly selected. Well, going back a long time in the evolution of bats they found a number of such genes. Standing out was the gene that encodes the protein called ISG15. In bats, there is a major difference from the human gene at a single amino acid! That makes the protein stronger in binding to viral particles inside of cells (good defense). Critically, the protein is excreted only weakly from cells. That reduces inflammation and damage to the animal.
The story may be deeper. Bats are the only mammals that fly. Flying stresses the animal’s metabolism and that can itself cause inflammation. Bats strongly limit this… and also inflammation from viral infections. Way to go, bats!
This has been an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org.
Source: Nature, 13 Feb. 2025, pp. 326 ff.
Image: Britannica
