The undertaker of the immune cell world has recently had a photoshoot, with researchers tracking the cell’s life cycle and function in real time.
“In living organisms, death happens all the time – and if you don’t clean up, the contents of the dead cells can trigger autoimmune diseases,” says Garvan Institute of Medical Research immunologist Professor Tri Phan.
Macrophages are immune cells that can ‘eat’ foreign material, like bacteria and viruses, and clean them up.
The researchers discovered that the specific lymph node macrophage they were looking at – called ‘tingible body macrophages’ – specialise in cleaning up the immune system’s own waste. Specifically, they eat up B cells which fight infections.
When a dead or dying B cell comes close, the macrophage reaches out and wraps around the target, pulling it in to be ingested.
The team used high powered microscopes on mice cells to peer into the inner workings of the immune system.
“A lot of what we do is like shooting a David Attenborough documentary, but at a microscopic scale – capturing the hidden life of these rare cells ‘in the wild’, to show how these cellular ecosystems work to keep us healthy,” Abigail Grootveld, a researcher at Garvan, and one of the first authors of the study.
This research is important because autoimmune diseases – like lupus – are poorly understood. We know that the immune system produces too many fighter T cells and B cells, and this causes inflammation and long term damage.
Because B cells are cleaned up by tingible body macrophages, they could have something to do with lupus.
The research has been published in Cell.