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A chemical connection that affects your immune system

A group of chemists, that includes Sander van Kasteren and Hermen Overkleeft, has discovered that azides, a certain type of chemical compound, can determine whether or not T cells respond to or ignore a vaccine. Their discovery is set to be published in Angewandte Chemie.

Organic azides

Organic azides are used on a large scale because they have two very useful properties: azides do not react at all, or have a limited reaction, to virtually all other chemicals, while they also form compact bio-orthogonal groups. They can be incorporated into a biomolecule and can be selectively modified. Scientists effectively use them as minuscule grips in experiments, as they are just a few atoms in size, enabling them to filter specific biomolecules from a complex mixture of cells.

Recognizing vaccines by turning T cells off…

Sander van Kasteren and Hermen Overkleeft, together with their team of chemists, have proven that these azides can be used not only for the ligation of molecules, but that they can also serve as a bio-orthogonal protecting group. During their search for model vaccines based on modified azides, the researchers discovered that converting an amine into an azide can stop a T cell, an immune cell, from identifying a vaccine.

…and turning them back on again

An equally important discovery was that this T cell can also be switched on again, using a Staudinger reduction. This reaction was discovered in 1919, and by applying it to the surface of a living cell, scientists can reduce the azide to an amine. The T cell will then recognize the vaccine again, demonstrating the usefulness of this ancient reaction as a bio-orthogonal protecting group.

A new impulse for chemical research

Possible applications of this new bio-orthogonal reaction have not yet been determined, but the expansion of the bio-orthogonal toolkit – which can now do more than ligate molecules – will give chemical studies of biological systems a new impulse.

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