Staphylococcus aureus bacteria (artificially coloured) were injected into mice to cause the severe condition called sepsis.Credit: Science Source/SPL
Genes that protect the body against infection during youth can do harm in old age, according to a study1 in mice. The results hint that ageing lowers immunity in unexpected ways, not just by weakening the immune response.
The study’s authors report that the presence of a specific gene in the heart helped mice to survive virulent infections — but only if the mice were young. For old mice, the gene increased the risk of death.
“In one case it’s protective. In another case, it actually drives death,” says Andrew Wang, an immunologist at Yale University in New Haven, Connecticut, who was not involved in the research. The study shows that “the mechanisms that are…