Waking up T cells to counteract chronic infections.

Memory T-cell responses generated in chronic viral infections can show functional defects contributing to poor viral control. Recently, signaling through the PD-1 receptor on CD8+ T cells was shown to cause cells to express an exhausted phenotype in an animal model of chronic infection. By blocking the interaction of PD-1 with its ligand PD-L1, virus-specific CD8+ T cells exhibited expansion and improved infection control. This approach could prove valuable to manage chronic infections.