The immune system: step it up or slow it down?

When foreign matter enters our body, our immune system has to make a choice whether or not to go on the attack. There are times when the system goes wrong, and we end up with an illness or an allergic reaction. Researchers at LUMC are trying to steer the immune system. The dossier on Immunity, Infection and Tolerance science describes their work.

Recognising parasites

The Leiden researchers are trying to either stimulate or slow down the immune system in the fight against illnesses or allergies. One example of such an attempt to activate the immune system is the Leiden research on a malaria vaccine. Every year more than half a million people die of malaria, particularly children below the age of five. A vaccine has recently become available. ‘That’s fantastic, but the vaccine only offers limited and temporary protection,’ Meta Roestenberg explains. She is a doctor of internal medicine and a specialist in infectious diseases at the Leiden University Medical Center (LUMC). ‘The malaria parasite has several stages of development that all look very different. This makes it difficult for the immune system to recognise the parasite.’ Added to this, the vaccine is based on only one of these stages, which means that a parasite in a different stage is able to evade the immune system.


Testing in humans

Roestenberg and her colleagues are currently developing a vaccine based on attenuated living parasites. These parasites are weakened by switching off two genes, which prevents them from causing the illness. Roestenberg: ‘In test animals this vaccine gives 100 per cent protection and we now need to test it on humans. It will take some time before the vaccine is readily available.’ Read more about this research in the dossier on Immunity, Infection and Tolerance science.

Defective immune cells

The dossier also gives examples of research on conditions where the immune system needs to be slowed down. In auto-immune illness like rheumatism and type 2 diabetes, the immune system attacks the body’s own cells. Leiden researchers are trying to find out what causes this. In the case of diabetes it is now clear which immune cells have become defective. This research represents a new type of cell therapy. The first tests on humans will take place shortly. In the case of rheumatism, the cause cannot be traced back to one single type of immune cell. Researchers are looking for ways of preventing the condition from becoming chronic.


At Leiden University researchers from different disciplines work together to create a safe, healthy, sustainable, prosperous and just world. You can read more about their research in our science dossiers. The dossier on Immunity, Infection and Tolerance is part of this series. Previous dossiers include:

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Dossier on Immunity, Infection and Tolerance

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Master's research track on Immunity, Infection and Tolerance

Last Modified: 05-11-2015