Ari Helenius: viruses under surveillance

A s any CIA operative will tell you, the best defense is to know your enemy. Ari Helenius, veteran vi-rologist, has spent the majority of his career learning the sneaky infi ltration tactics of human and animal foes such as infl uen-za, vaccinia, and herpes simplex virus. And their tactics are many and varied. Helenius learned that Semliki Forest virus, for example, enters cells via endosomes and bursts into the cytoplasm when the en-dosome's acidic environment triggers fusion of the virus's membrane with that of the endosome (1). Vaccinia virus, on the other hand, fi rst surfs the length of fi lopodia to the cell surface and then impersonates cell debris , tricking the host cell into gobbling it up (2). Helenius's work on viruses has also led him into studies on more general aspects of cell biology. He has published extensively on the topic of endocytosis (3) and also protein folding (4). How did you get started in science? At the age of 17, I was chosen as an exchange student to go to the States. There was a program called the American Field Service. It was originally started by the Quakers, who had set up an ambulance service during the First and Second World Wars. After the Second World War, they decided not to dismantle their organization but instead to start something that might help prevent future wars. The exchange program brings high school students from all around the world to study for one year in the States and to live with American families. I think 70 or so students are chosen from Finland every year. I went in 1961 and stayed with a family in Pennsylvania. It was an interesting phase for Ameri-can education, because the Russians had recently succeeded in launching the Sputnik satellite, and the Americans were shocked by this event and poured huge amounts of money into science education. I happened to be there at just the right time. My high school education in chemistry was extremely good. I was surrounded by a very enthusiastic group of students, and had a great teacher. I was totally taken by the whole thing, and decided to become a chemist. So I think the key thing that got me started in science was the excellence of the American high school education. You don't think this would have happened had you stayed in Finland? No. I was always …