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Ruth Itzhaki

Why did you decide to study physics?

I found it exciting to try to understand how things happen, and I liked pure maths very much. Later, I began to think that perhaps the science of living things was even more fascinating than the science of phenomena such as light and electricity, and that’s how I got into biophysics. I wanted to know how things click, and what’s happening in a cell, not that I knew what a cell was, because in those days, one had to choose maths, physics and chemistry at school before studying physics at university, so I hadn’t done any biology. When I was doing my MSc in biophysics at the Institute of Cancer Research and University College London, we were thrown into the deep end; I think the first tutorial I had was about nerve transmission, and I didn’t even know what those words meant. Changing over to biophysics was a major effort.

What did you do after your MSc?

I went on to earn my PhD in biophysics, and after that I moved to Cambridge, where my husband was. I had postdoctoral fellowships investigating the structure of chromatin, the chemical that makes up chromosomes, using a method called electric birefringence, I think the idea was that I could use my physics. Later, my husband got a post at the University of Manchester and I moved there with him to take up a post at a cancer research institute. This was considered a major change, in fact I was told by the institute’s director, who was a Machiavellian monster, What’s the point of looking at chromatin? Eventually, I’d had enough, so I moved to another lab where I started working on viruses, which was very interesting indeed, and that’s more or less what I’ve been doing since.

What are you working on now?

For the last 25 years or so I’ve been working on the possibility of viruses being involved in Alzheimer’s disease. There are three major reasons for thinking this. The first is that the particular virus we’re interested in, the cold sore virus, herpes simplex type 1, can cause a very rare but serious disease called herpes simplex encephalitis where it damages exactly the same regions of the brain as those damaged in Alzheimer’s disease. The second reason is that this virus has a propensity for lying latent in the body. Many people are infected in infancy and once infected the virus stays with them for life. And finally, it’s known that a number of viruses can cause diseases in the brain. But we needed initially to find whether this virus was actually present in the brain, so we used a very sensitive method called polymerase chain reaction to look for viral DNA in extracts of the brain, and we found that it was indeed present in a high proportion of elderly people.

How does the virus contribute to Alzheimer’s?

We think what happens is that as people age, and their immune system becomes less effective, the virus travels to the brain and initially lies latent there, but it can be reactivated by events like stress or immunosuppression. Under those conditions, it starts replicating and causes damage, including the production of the abnormal proteins seen in Alzheimer’s brain. If that happens repeatedly, you get an accumulation of damage, which we think is one cause of Alzheimer’s. We’re not saying it is the cause, but that it’s a major cause. We found that it almost certainly acts with a genetic factor that is a known susceptibility factor for Alzheimer’s: if the virus is in the brain of people who have this particular genetic factor, then they have a high risk of developing the disease. There’s been a huge amount of hostility to this idea, which is now, I think, slowly being overcome, as a lot of other people have got into the field and confirmed our results.

How (if at all) has your physics background influenced your work?

I think it makes one more probing, but it was actually a bit of a hindrance initially because I wanted to be more precise than is possible in the biological sciences. A senior person in the lab where I did my PhD told me, Ruth, you’ve got to understand you can’t be as exact as you were when you were doing physics. Just be honest about it, that’s all that matters. I wanted to get to the heart of things, and I’m not terribly interested in detail, although obviously one has to prove as conclusively as one can that one’s experiments have been done properly. But I’d rather look at something basic in the problem than at the minutiae. I wouldn’t have been good at X-ray crystallography, too many minutiae there!

Any advice for today’s physics students?

Be prepared to persevere even if people don’t necessarily understand or believe in what you’re doing. If you think you’re right and you have enough evidence, just carry on and try as hard as you can. And enjoy your work as much as you can. It’s terribly exciting when one makes a major discovery. It really is extraordinary; it compensates for all the setbacks.