Detection and Isolation of a Drug-Resistant Influenza Virus Using a Sialidase Fluorescence Imaging Technique

Neuraminidase (NA), which is expressed on the membrane surface of an influenza virus, plays a critical role in the growth of a virus exhibiting sialidase activity, and this activity is a target for therapeutic drugs. The authors have developed a novel substrate, BTP3-Neu5Ac, that is capable of fluorescence imaging of sialidase activity and have developed a method for detection of influenza virus by fluorescence imaging of sialidase activity. The method has been applied to the detection and isolation of a drug-resistant influenza virus. Water-soluble BTP3-Neu5Ac undergoes hydrolysis by sialidase resulting in the liberation of sialic acid and generation of free BTP3. BTP3 is deposited and enabling fluorescence imaging of sialidase activity. Fluorescence imaging of the sialidase activity of influenza virus NA enables convenient and rapid detection of viruses and infected cells. A drug-resistant influenza virus, which has become a problem in recent years, is a virus that has acquired by mutation resistance to a sialidase inhibitor and retains its activity even in the presence of a sialidase inhibitor. The authors have therefore developed a method for selective detection of a drug-resistant influenza virus. BTP3-Neu5Ac for detection and isolation of a drug-resistant influenza virus is expected to be widely used in the future as a useful tool in basic research, hygiene and clinical fields.