Recent studies immune system induces invaded fungal spores in the lungs in the suicide

Scientists discover protective mechanism of the immune system in the lungs
It is known that patients who suffer from an unstable immune system in the course of a serious illness, more often become ill with fungal infections. An international research team has discovered how the human immune system protects against fungal infections. The results of the study may be groundbreaking to free patients from fungal infections. The study involved researchers from the University of Göttingen.

With every breath we pick up fungal spores in the lungs. There, the fungi can cause life-threatening infections. Scientists from Germany, Israel and the US have now found out that the human immune system triggers a kind of suicide mechanism in the fungal spores in the lungs, which causes the fungal spores to destroy themselves. The results have been published in the journal Science.

Fungal infections can even be fatal. (Image: Dr_Kateryna / fotolia.com)

Fungal infections in weakened immune system
The intact immune system and a well-populated intestinal flora succeed without difficulty to break down invading fungal cells or to prevent overgrowth by (anyway) existing in the body populations. However, if the immune system is weakened by pre-existing conditions or if the body's own defense mechanisms are diminished by frequent ingestion of medications, in particular antibiotics, the fungi can spread unhindered.

Invasive fungal infections kill as many people worldwide each year as malaria or tuberculosis. In people with a weakened immune system, spores can travel through the lungs into the blood and from there into organs, including the brain. This can lead to dangerous mycoses, which often end in death. Researchers now looked into why people with intact immune systems do not get sick more often, even though we breathe up to ten billion fungal spores every day, and how an intact immune system prevents fungal spores from spreading in the body.

"We have found that our human neutrophil immune cells in the lungs trigger a kind of suicidal mechanism in the fungal spores," explains Prof. Dr. med. Gerhard Braus, Head of the Department of Molecular Microbiology and Genetics of the University of Göttingen.

Triggered suicide
Fungal spores have a protective protein against fungal suicide (Bir1). "If fungal spores reach the lungs, the immune cell sends out a signal that switches off the protective protein Bir1," says Braus. "As a result, the fungal spore itself is destroyed." If a fungus contains more genes for Bir1 and therefore more Bir1 protein than normal, the fungal spore remains protected and does not destroy itself. The results of the study could provide the basis for new therapeutic strategies to cure patients with fungal infections. (Sb)

Original publication: Neta Shlezinger et al. Sterilizing immunity in the lung relies on targeting fungal apoptosis-like programmed cell death. Science 2017. Doi: 10.1126 / science.aan0365