The protein called retrocyclin-101 (RC-101) is unique in that it not only targets the flu virus itself, but also the harmful inflammation the virus triggers in the host. While the effect of RC-101 has been studied as a flu treatment in cells before, it has never been studied in animals.
"Every year, thousands of people across the country die from the flu or its complications - despite widespread use of annual influenza vaccines," said Daniel J Prantner, a research associate at the University of Maryland in the US. "We think that this protein could lead to medicines that could be a powerful tool in the battle against this disease, and against inflammation in general," said Prantner.
For the study, published in the Journal of Leukocyte Biology, researchers studied the effects of RC-101 on human cells, and in an animal model of flu, using mice. They studied human immune cells, and found that RC-101 had two positive effects.
First, it blocked the flu virus from infecting the cells; second it blocked the runway inflammation that is behind most symptoms of influenza infection, such as fever, pain, lethargy, and trouble breathing. This double action is unique, Prantner said. In the animal model, researchers infected two groups of mice with a dose of influenza that is typically lethal. They gave one of these groups RC-101 two days after infection for a total of five days, and gave the other group a placebo.
The mice that were treated with RC-101 exhibited less severe symptoms of the flu and also decreased rates of death. Among the control group, 90 per cent of the mice died; among the group that was given RC-101, only 20 per cent died.
Although RC-101 does not exist in humans, it does exist in some other animals, including orangutans, and provides powerful antiviral protection. It appears to have been lost over the course of recent primate evolution. Chimpanzees and gorillas, for example, do not have it....