Immune cells called plasmacytoid dendritic cells (pDCs) are the most potent producers of type I interferons—molecules important in regulating the immune system, contributing to inflammation and autoimmunity, and mediating responses to SARS-CoV-2 and other viruses. To understand how pDCs are primed to produce interferons, Gregoire Lauvau, Ph.D., David Fooksman, Ph.D., and colleagues used intravital multi-photon imaging to study a mouse model of severe malaria in which type I interferon negatively affects clinical outcome.  

The researchers found that the first event in interferon production occurs when CD169+ cells—macrophages in the bone marrow that express the surface molecule CD169+—ingest red blood cells infected with Plasmodium, the single-cell parasite that causes malaria.  After ingesting the parasite, the macrophages signal pDCs to remain in the bone marrow and to secrete type I interferons before exiting into the bloodstream. Targeting these cellular interactions could help to better control infections and prevent autoimmune diseases. The findings were published online on October 24 in eLife. 

Dr. Lauvau is professor of microbiology & immunology at Einstein. Dr. Fooksman is an associate professor of pathology and of microbiology & immunology at Einstein.