For the first time, scientists have successfully observed influenza viruses infecting living cells in real time and high resolution. This breakthrough, facilitated by a novel microscopy technique, marks a significant step forward in understanding viral behaviour and developing targeted antiviral therapies.
As winter approaches, influenza re-emerges, bringing with it familiar symptoms such as fever and aching limbs. The disease is caused by influenza viruses that infiltrate the body through droplets, eventually infecting cells. Researchers from Switzerland and Japan have meticulously examined this viral process. By employing a microscopy technique they developed, they have managed to observe how influenza viruses penetrate living cells in unprecedented detail.
Led by Professor Yohei Yamauchi of ETH Zurich, the research team was particularly intrigued by the active role cells play during infection. “The infection of our body cells is like a dance between virus and cell,” Yamauchi noted. This dynamic interaction occurs as viruses exploit a vital cellular uptake mechanism, typically used for substances like hormones and cholesterol.
Influenza viruses attach to molecules on the cell surface, scanning for an optimal entry point enriched with receptor molecules. Upon attachment, the cell membrane forms a pocket, supported by clathrin proteins, which encapsulates the virus in a vesicle. This vesicle is then transported inside the cell, where it releases the virus.
Previous studies using electron microscopy and fluorescence microscopy were limited, as they either destroyed the cells or provided low-resolution images. The new ViViD-AFM technique combines atomic force microscopy and fluorescence microscopy, allowing detailed observation of viral entry dynamics.
The study has demonstrated that cells actively assist in virus uptake by recruiting clathrin proteins and adapting their membrane to capture the virus. The technique presents significant implications for developing antiviral drugs, offering a platform for real-time efficacy testing. Researchers suggest that this method could also be applied to study other viruses and vaccines.
