Apoptotic cell identity induces distinct functional responses to IL-4 in efferocytic macrophages. (https://pubmed.ncbi.nlm.nih.gov/38574142/)

These scientists wanted to understand how certain cells in our body, called macrophages, respond to different types of dying cells. They found that when macrophages are in an environment with a specific molecule called interleukin-4 (IL-4) and they encounter dying neutrophil cells, they start changing the way they work to help remodel tissues in our body.

When the macrophages engulf dying liver cells (hepatocytes), they become more tolerant, but when they engulf dying T cells, they don't change much in response to IL-4. In a study with mice infected by parasites, the scientists discovered that transferring these IL-4-conditioned macrophages that had engulfed dying neutrophils helped the mice clear the parasites.

By studying this, the scientists learned that the type of dying cell that macrophages encounter can affect how they respond to IL-4 and how they help the immune system fight off infections.

Liebold I., Al Jawazneh A., Casar C., Lanzloth C., Leyk S., Hamley M., Wong MN., Kylies D., Grafe SK., Edenhofer I., Aranda-Pardos I., Kriwet M., Haas H., Krause J., Hadjilaou A., Schromm AB., Richardt U., Eggert P., Tappe D., Weidemann SA., Ghosh S., Krebs CF., A-Gonzalez N., Worthmann A., Lohse AW., Huber S., Rothlin CV., Puelles VG., Jacobs T., Gagliani N., Bosurgi L. Apoptotic cell identity induces distinct functional responses to IL-4 in efferocytic macrophages. Science. 2024 Apr 5;384(6691):eabo7027. doi: 10.1126/science.abo7027. Epub 2024 Apr 5.