Newsroom

With advancing age, a person's immune system often grows weaker. One reason behind this is the gradual decline of the stem cell population that the body draws on in its ongoing effort to replace old worn-out or damaged immune cells. Now, scientists at the University of Ulm, Germany, in collaboration with the Helmholtz Centre for Infection Research (HZI) in Braunschweig, Germany, have at last identified the mechanism underlying age-related immune function loss. Although it takes place in all cells of the body throughout a person's life, the accumulation of DNA damage in certain blood stem cells activates a gene critical for their differentiation into mature defender cells - a process, which compromises the stem cells' capacity for continuous, lifelong self-renewal, and ultimately responsible for their loss. The researchers' findings are published in the renowned scientific journal Cell and are in fact the current issue's cover story.

In medieval Europe, the Black Death once decimated large parts of the population. Although in Europe no longer a genuine cause for concern, in Africa, South America, and India the Bubonic plague still to this day poses a viable threat to public health. The culprit behind the pandemic is a bacterium of the genus Yersinia. Each year in Germany, the pathogen's slightly less virulent relative is responsible for causing several thousand cases of diarrheal disease – often times with serious consequences. Scientists at the Helmholtz Centre for Infection Research (HZI) in Braunschweig, Germany, working closely with their colleagues at the Ruhr University in Bochum, Germany, have identified a mechanism that enables these bacteria to turn on their weaponry once inside the host. It turns out that Yersinia possesses a built-in molecular thermometer that jump-starts the bacterial pathogenic program at precisely 37 degrees Celsius, which corresponds to normal human body temperature.