Among most animal species, humans included, females tend to live longer than males. A number of theories has been advanced over the years to explain this gender-based survival advantage. Now, new research from Japan suggests a reason that can be tested: women’s immune systems age more slowly.
A research team at Tokyo Medical and Dental University analyzed blood samples from 356 healthy men and women between the ages of 20 and 90. In particular, they measured levels of white cells and cytokines, molecules that interact with immune system cells to regulate the body’s response to disease.
As expected from prior research, the investigators found that white blood cells declined with age, but they also observed two key differences between the sexes: in men they recorded a steeper decline of T-cells that protect against infection and B-cells which secrete antibodies. They also found that the expected age-related increase in natural killer cells and CD4 T-cells, which attack invaders, rose at a higher rate in women than in men. Elsewhere, similar findings have been seen in mice.
