For increase a person's natural resistance to viral infection a small family of flu-fighting proteins has been identified, US scientists claimed.

According to reports in the journal Cell on Thursday, for guarding cells from an attacking virus that causes influenza a family of genes act as cell sentries.

IFITM3, a specific protein in the flu fighting protein family was able to protect against several viruses. This included strains of influenza now found in seasonal flu, the West Nile virus and dengue virus, reports stated.

Harvard Medical School Professor Stephen Elledge, one of the researchers, said, "We've uncovered the first-line defense in how our bodies fight the flu virus. The protein is there to stop the flu. Every cell has a constitutive immune response that is ready for the virus."

A geneticist and instructor of medicine at Harvard Medical School and Massachusetts General Hospital Dr Abraham Brass led the study and said, "When we knocked the proteins out, we had more virus infection. When we increased the proteins, we had more protection."

Using a new research technique called RNA interference, Elledge and colleagues, systematically turned off individual genes and then exposed cells to the flu virus. They found out a small family of flu-fighting proteins called interferon-indicible transmembrane proteins that helps body guard against viral infections better.