T helper-17 cells, which are involved in immune responses, arise from a pool of precursor cells. It emerges that their differentiation is partly mediated by the IL-21 protein, which originates from the helper cells themselves.

Origami, the ancient Japanese art of paper folding, is mathematically deeper than it looks. Delving into its complexities allows the construction of elaborate and useful structures from simple, flat templates.

In multiple sclerosis, the immune system attacks 'self' tissues. Ten years after the discovery of one target of this autoimmunity, work with mice identifies it as a guardian protein produced in response to inflammation.