This image shows inflammed lung tissue with immune cells that have migrated into the lungs. Their nuclei are stained blue.

This image shows inflammed lung tissue with immune cells that have migrated into the lungs. Their nuclei are stained blue.

Apoptosis is used by cells that are changed by disease or are simply not needed any longer to eliminate themselves before they become a hazard to the body—on a cellular level, death is part of life. Disruption of this process can lead to cancer or immunodeficiencies, but also to autoimmune diseases, in which cells attack their own body.

Researchers examined the role of central proteins, called c-FLIP proteins, which inhibit signaling cascades that can lead to apoptosis. This is important temporarily in the response to pathogens to ensure that lymphocytes, a type of immune cells, can proliferate sufficiently.

Towards the end of the immune response, once the lymphocytes completed their tasks and successfully eliminated the pathogen, c-FLIP is usually degraded. As a result, apoptosis is enabled again, the lymphocytes die and the equilibrium in the immune system is restored.

The HZI researchers then took a closer look at the exact function of a certain variant of the protein, called c-FLIPR. They used mice to investigate what happens if this protein is always present in lymphocytes and other blood cells.