To reproduce itself in the human body, a virus will actually invade our cells and take over the cells’ mechanics. This is why most treatment option wills focus on developing a defense system within our cells. A laboratory-based investigation led by the University of Pittsburgh Cancer Institute (UPCI) and UPMC Cancer Center has discovered a naturally occurring protein in human cells that may improve our ability to identify and treat viral infection such as influenza and hepatitis C.

"Despite remarkable advances in vaccination and treatment, diseases caused by viral infections remain among the leading causes of death worldwide," Dr. Saumendra N. Sarkar, assistant professor of microbiology and molecular genetics at UPCI, said in a statement. "We need new defenses against viral infections, and our discovery is proving to be a promising avenue for further exploration."

Sarkar and his colleagues isolated oligoadenylate synthetases-like (OASL), a protein that appears quite often in people suffering from liver cancer caused by the hepatitis C virus. When researchers enhanced this protein in human cells, they noted the inhibition of viral replication. Further testing found mice without OASL were significantly more susceptible to viral infection compared to those with the protein. The research team hopes their findings will translate to more effective treatments for viral infection, ranging from the flu to hepatitis C.

Ribonucleic acid (RNA) viruses including hepatitis C, influenza, and Respiratory Syncytial Virus Infection (RSV) use RNA as genetic material when they replicate. Treatments based off of the OASL protein could enhance our cells’ ability to detect RNA used by the virus and activate the immune system to stop its replication. Interferon, a similar natural occurring protein that is produced and released by cells to combat viruses, is currently used in hepatitis C treatment, but it is unsuccessful in treating influenza. Interferon treatment can also result in adverse side effects such as fatigue, headaches, fever, and nausea.

"The respiratory system is a much easier target to deliver this type of therapy, compared to an organ, such as the liver, so we'll be starting with infections like RSV," Sarkar added. "From there we could branch out to other RNA viruses and perhaps find effective ways to boost our inherent immunity against a broad range of viral infections."

Source: Cuevas R, Forero A, Sarkar S, et al. Antiviral Activity of Human OASL Protein Is Mediated by Enhancing Signaling of the RIG-I RNA Sensor. Immunity. 2014.