Press releases
Please quote Nature Immunology as the source of these items.
The September 2008 issue of Nature Immunology is available online.
September 2008
Mediating restraint
Scientists have uncovered how lung tissues avoid excessive damage in response to airborne irritants and infections. The findings reveal important insights into the possible treatment of patients with complications triggered by respiratory infections.
Lungs are delicate tissues that are constantly exposed to multiple inhaled microbes and microscopic particles. Excessive inflammation leads to scarring, which could interfere with lung gas-exchange function.
Online in Nature Immunology this week, Tracy Hussell and colleagues report that a molecule called CD200R exerts a dampening effect on specific immune cells residing in the lung. CD200R acts to increase the threshold required to activate an immune response in the lungs. Once such a response is initiated, CD200R reduces lung inflammation, lessening damage to lung tissues. Mice lacking CD200R had a lower survival rate in response to influenza infection, despite maintaining the ability to control this virus. Death was due to excessive collateral tissue damage brought about by the unrestrained immune cells.
A critical function for CD200 in lung immune homeostasis and the severity of influenza infection
Robert J Snelgrove, John Goulding, Arnaud M Didierlaurent, Daphne Lyonga, Seema Vekaria, Lorna Edwards, Emily Gwyer, Jonathon D Sedgwick, A Neil Barclay & Tracy Hussell
Published online: 27 July 2008 | doi 10.1038/ni.1637
Avoiding attack when not stressed
Healthy cells express a panel of microRNAs that help avoid unwanted recognition and attack from the immune system. A study online in Nature Immunology this week explains this process, and suggests the same mechanism may also help tumours to go undetected.
MICA and MICB proteins—upregulated in times of stress such as a viral infection—are recognized by the receptor NKG2D expressed on immune cells. Detection of these stress-induced proteins by these cells triggers an immune response that clears the source of stress. Viruses can evade this immune response using short stretches of RNA called microRNAs that suppress MICA and MICB expression.
Ofer Mandelboim and colleagues show that, like viruses, healthy non-stressed human cells also express microRNAs designed to dampen MICA and MICB expression. This allows healthy cells to escape detection by the immune system. Compared to healthy tissues, many human tumours express excessive amounts of these microRNAs. Importantly, this might also help tumours escape recognition by the immune system.
Human microRNAs regulate stress-induced immune responses mediated by the receptor NKG2D
Noam Stern-Ginossar, Chamutal Gur, Moshe Biton, Elad Horwitz, Moran Elboim, Noa Stanietsky, Michal Mandelboim & Ofer Mandelboim
Published online: 01 August 2008 | doi 10.1038/ni.1642
