Study gene protects against flu and other viruses

Study: Gene protects against flu and other viral diseases

27.03.2012

The gene IFITM3 protects against flu and other viral diseases. This resulted in one in the journal „Nature“ published study. If the gene is missing, a generally harmless flu in mice develops into a life-threatening form, similar to the Spanish flu. Patients who had to be hospitalized for the swine flu H1N1 / 09, according to the study had flawed versions of the IFITM3 gene.

Without the gene severe illnesses of the flu
IFITM3 sits on chromosome 11 and contains the genetic information for that „interferon induced transmembrane protein 3“. The gene belongs to the interferon response to viral infections. Already in previous studies a connection between the IFITM3 gene and the defense of West Nile fever, influenza A and dengue could be established. Aaron Everitt of the Wellcome Trust Sanger Institute in Hinxton, Cambridge, and his co-workers now conducted systematic studies of the role of the gene for the first time. For this, the IFITM3 gene was knocked out by knockout mice. The scientists were then able to observe severe disease patterns in the animals. Mice, who usually had mild flu, now had strong symptoms of influenza. In addition, they lost more than 25 percent of their weight.

IFITM3 gene is only one of many causes
Normally, mice eliminate the virus from their lungs within two days. The knockout mice with the IFITM3 gene switched off were still alive after one week, although the infection was restricted to the lungs as well. Everitt's conclusions indicate that the IFITM3 gene plays a crucial role in immune defense. To confirm this, the scientists studied 53 people hospitalized for severe swine flu. In three of the patients studied, they discovered a mutation that leads to the formation of truncated IFITM3 proteins. Such a mutation is usually much less common in only one in 400 people. Everett concludes that an altered IFITM3 gene is responsible for the severe course of the flu. Since the mutation was found only in a few patients, it can be assumed that there are other causes. The scientists will have to look for further mutations in interferon metabolism in the future. At some point genetic analysis may be used to diagnose increased susceptibility to viral diseases. Those affected could then be vaccinated accordingly. (Ag)

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Picture: Rita Thielen