A team of Professor Gyun-hwan Kim (Pharmacology) at Konkuk University's Medical Graduate School has identified key factors and their principles that cause toxicity in the Spanish flu virus.The Spanish flu that occurred in 1918 is believed to be the deadliest infectious disease in human history, with over 50 million casualties. Such a high-risk flu (influenza) infection can cause enormous loss of life and economic damage to the nation.Professor Kyun-Hwan Kim and Eun-sook Park of Konkuk University and Professor Baik-lin Seong (first author) of Yonsei University and Professor Kwang-Pyo Kim of Kyung Hee University noted that there is a mutation in the protein called 'PB1-F2' It has been shown that this strongly inhibits interferon beta *, which acts as an antiviral of our bodies, to increase virulence * of the virus. *Interferon beta (IFNb): One of the substances induced in the early immune system to eliminate it when infected with a virus or certain bacteria *Virulence: The ability of a pathogen to cause disease or death to a host.This characteristic only occurs when there is a mutation in the amino acid at a specific position of the PB1-F2 protein, such as the Spanish influenza virus, and the common influenza with no mutation and weak virulence did not show this property.The mutant PB1-F2 strongly inhibits the induction of interferon beta by degrading the essential protein 'DDX3' involved in interferon signaling. This leads to disease and death due to the virus.Professor Kim said that "This study has identified a new pathogenesis of the Spanish influenza virus, and it can be applied to the development of a new type of high-risk influenza infection treatment, and by identifying mutations at specific sites, it is possible to detect and predict new methods of detecting high-risk viruses such as the Spanish flu."Professor Eun-Sook Park said, "The Spanish flu has recorded the highest mortality rate among infectious diseases experienced by mankind, and now 100 years later, it is possible to interpret its high virulence." Recently, a serious illness is emerging as the alarm is ringing."The results of this research were carried out by the Ministry of Science and Technology, Ministry of Information and Communication, Korea Research Foundation Basic Research Project, and Biomedical Technology Development Project, and published in the international journal "EMBO Journal" on April 12. The title of a paper: Co-degradation of interferon signaling factor DDX3 by PB1-F2 as a basis for high virulence of 1918 pandemic influenza