Protein essential for immune recognition and response to viral infection identified

Researchers have identified an immune cell protein that is critical to setting off the body's initial response against viral infection.

The report describes that a protein called GEF-H1 is essential to the ability of macrophages - major contributors to the innate immune system - to respond to viral infections like influenza.

Senior author Hans-Christian Reinecker, MD, of the Center for the Study of Inflammatory Bowel Disease in the MGH Gastrointestinal Unit, said that the detection of viral genetic material inside an infected cell is critical to initiating the responses that signal the immune system to fight an infection and prevent its spread throughout the body.

He said that their findings indicate that GEF-H1 may control immune responses against a wide variety of RNA and DNA viruses that pose a threat to human health.

GEF-H1 is known to bind to microtubules, and previous research indicated that it has a role in immune recognition of bacteria.

A series of experiments by Reinecker's team found that GEF-H1 is expressed in macrophages - key components of the innate immune system - and activated in response to viral RNA and that it controls the expression of beta interferon and other cytokines.

Mice in which expression of GEF-H1 was knocked out were unable to mount an effective immune response to influenza A and to encephalomyocarditis, a virus that causes several types of infection in animals.

The study has been published in the upcoming journal of Nature Immunology.