On the cover: Protective immune response after CNS injury. Arginase 1 (green) expressing macrophages [CD68⁺ (red)] in the injured optic nerve. This injury-associated protective phenotype of macrophages is supported by effector T cells and attenuated by regulatory T cells. Image courtesy of Jingjing Zheng. Walsh, J. T., J. Zheng, I. Smirnov, U. Lorenz, K. Tung and J. Kipnis. 2014. Regulatory T cells in central nervous system injury: A double-edged sword. J. Immunol. 193: 5013–5022.