@article {542461,
	title = {PD-1 and its ligands in T-cell immunity.},
	journal = {Curr Opin Immunol},
	volume = {19},
	number = {3},
	year = {2007},
	month = {2007 Jun},
	pages = {309-14},
	abstract = {The past year has seen significant advances in our understanding of the critical roles of negative immunoregulatory signals delivered by the programmed death 1 (PD-1)-PD-1 ligand (PD-L) pathway in regulating T-cell activation and tolerance. Emerging evidence indicates that PD-Ls play an essential role on dendritic cells (DCs), both directly during DC-T cell interactions and indirectly through signaling into the DC. Recent studies point to a novel role for PD-L1 in maintaining tissue tolerance. Finally, PD-1 has recently been shown to be highly expressed on exhausted T cells during chronic viral infection, and blockade of PD-1 or PD-L1 can revive exhausted T cells, enabling them to proliferate and produce effector cytokines.},
	keywords = {Animals, Antigens, CD, Antigens, CD274, Apoptosis Regulatory Proteins, Cell Communication, Dendritic Cells, Humans, Immune Tolerance, Lymphocyte Activation, Programmed Cell Death 1 Receptor, T-Lymphocytes},
	issn = {0952-7915},
	doi = {10.1016/j.coi.2007.04.012},
	author = {Keir, Mary E and Francisco, Loise M and Sharpe, Arlene H}
}
