On the cover: Double negative T cells are a major component of kidney αβ T cells. Kidney mononuclear cells were isolated from B6 mice or humans, stained, acquired by LSR II and analyzed using FlowJo. DN T cells were identified as CD45⁺TCRβ⁺CD4⁻CD8⁻ using sequential gating as shown. NKT cells were excluded using α-GalCer-tetramer staining. DN T cells represent a unique population of kidney T cells. Activation and proliferation of PD-1⁺ DN T cells is dependent on non-classical MHC proteins and interleukin-2. Hamid Rabb et al., Johns Hopkins University, Baltimore, Maryland