In the Net

It’s an act of self sacrifice that corners the enemy and rallies comrades to the cause. Neutrophils (immune cells pictured, orange) detect invading microbes and counter threats with kamikaze spirit. They die off while valiantly emitting neutrophil extracellular traps (NETs, green), composed of antimicrobial proteins and genetic material, that capture bacteria (pink) like flies in a spider web. A new study has revealed how NETs also spur macrophages, other immune system components, into action. Macrophages engulf the NETs and the DNA material from them stimulates sensors inside the macrophage. This leads to the production of type 1 interferons, molecules that limit the spread of infections and further invigorate the immune system. In this way neutrophils leave a legacy of defence as reinforcements arrive in their wake. If new treatment approaches build on this mechanism for encouraging interferon release in patients, their lasting impact could be even greater.

Written by Anthony Lewis

Image by Volker Brinkmann on the cover of Science Signaling March 2021, Max Planck Institute for Infection

Research by Falko Apel and colleagues, Max Planck Institute for Infection Biology, Department of Cellular Microbiology, Berlin, Germany

Image copyright held by Volker Brinkmann, reproduced with permission

Research and image published in Science Signaling, March 2021

In severe cases of COVID-19, a person’s immune system throws everything it has at the coronavirus, but some of the weapons it lobs end up hurting the patient instead of fighting the virus.  

Now researchers have new clues for getting the immune system back on target, before the disease becomes severe. One of the most comprehensive looks to date at the immune system of COVID-19 patients pinpoints where things go awry. The findings suggest that bolstering the body’s first line of defense against the virus using drugs known as interferons may help prevent severe illness.

In a study of 113 patients admitted to Yale New Haven Hospital from May 18 to May 27, researchers monitored immune system chemicals and cells in two groups: severely ill COVID-19 patients who needed intensive care and moderately ill patients who were hospitalized but didn’t end up in the ICU. For comparison, the team also looked at healthy health-care workers.

How the virus gets into respiratory tissue — and how it may exploit one of our defenses

What makes SARS-CoV-2, the virus behind COVID-19, such a threat? A new study, led by Jose Ordovas-Montanes, PhD at Boston Children’s Hospital and Alex K. Shalek, PhD at MIT, pinpoints the likely cell types the virus infects. Unexpectedly, it also shows that one of the body’s main defenses against viral infections may actually help the virus infect those very cells. Findings were published April…