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“We think carefully about how many mice are necessary”

Prof. Dr. Alfred Zippelius
Prof. Dr. Alfred Zippelius. (Photo: University of Basel, Christian Flierl)

Professor Alfred Zippelius, from the Department of Biomedicine at the University of Basel, has been conducting experiments with mice for several years. In this interview, he explains why he decided to do this and how it advances his research in cancer immunotherapy.

10 January 2022

Prof. Dr. Alfred Zippelius
Prof. Dr. Alfred Zippelius. (Photo: University of Basel, Christian Flierl)

Professor Zippelius, why did you start doing experiments with mice 11 years ago?

During my research career, I worked for many years without animal experiments and only did experiments with human cells. Then I had a question where I simply couldn’t move forward any further, and I integrated animal experiments into my work. If you look at my laboratory today, it’s interconnected. Either we start from a very specific question using animal experiments and then validate the result in humans, or we’re faced with a problem in a patient, which we then try to answer using an animal model.

What do animal experiments offer compared with human trials?

Research on humans is in some ways very descriptive. We receive tumors from patients and can then take a snapshot of the tumor cells and immune cells in the test tube. But there is no longer any influx or efflux. For example, there are no lymph nodes – the structures in which an immune response occurs. That’s where the T-cells are formed, which then migrate to the tumor. In order to research fundamental biological mechanisms such as these, and to answer certain questions, we require a closed system. And we can only do that in mice.


In animal experiments, the aim is to minimize the animals’ suffering as far as possible. Do you think about that aspect as well?

Of course we impose strict conditions on ourselves. Since I’m generally no longer the one that conducts the experiments, we’ve had a lab technician working in my group for years who is solely responsible for animal experiments. This guarantees that the mice are looked after according to specific guidelines and everything is well documented. She also gives the researchers a rap on the knuckles if necessary.

We have strict criteria on how we approach animal experiments. For example, we concentrate on the most important questions, avoid unnecessary experiments and think carefully about how many mice are necessary in order to obtain statistical significance. We have to account for all this very precisely in our animal experiment application.

You are not only a researcher, but also the deputy head of oncology at the University Hospital of Basel. Does your contact with cancer patients influence how you weigh the benefits to humans against the suffering of animals?

I think it makes a strong impression, of course. I was once asked whether I thought animals were worth less than people. It’s an important ethical question. But at the end of the day I have to admit that the cancer patient who sits in front of me with their fate hanging in the balance means more to me at that moment. Practically all the modern cancer drugs that we have available today were developed using animal experiments. There is currently still no other way to do it.

Initiative to ban animal and human experiments

On 13 February, Switzerland will vote on the federal popular initiative “Yes to the ban on animal and human experiments – Yes to research that brings safety and progress”. It aims to ban all experiments on animals and humans, as well as the trade, import and export of products, such as medicines, for which animal testing or clinical trials have been carried out.

Swissuniversities, the umbrella organization of Swiss higher education institutions, warns of a medicine and research ban. Accepting the initiative would prevent above all biomedical research and the development of new medical treatment methods. The issues at stake include the high quality of healthcare and responsible research in Switzerland in the service of the population and the environment.

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