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Updated: Jun 6, 2026

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes
Published on: September 28, 2018
Role of PD-1 in regulating T-cell immunity
Hyun-Tak Jin1, Rafi Ahmed, Taku Okazaki
1Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA.
Abstract:
Programmed cell death-1 (PD-1) is a member of the CD28 superfamily that delivers negative signals upon interaction with its two ligands, PD-L1 or PD-L2. PD-1 and its ligands are broadly expressed and exert a wider range of immunoregulatory roles in T cells activation and tolerance compared with other CD28 members. Subsequent studies show that PD-1-PD-L interaction regulates the induction and maintenance of peripheral tolerance and protect tissues from autoimmune attack. PD-1 and its ligands are also involved in attenuating infectious immunity and tumor immunity, and facilitating chronic infection and tumor progression. The biological significance of PD-1 and its ligand suggests the therapeutic potential of manipulation of PD-1 pathway against various human diseases. In this review, we summarize our current understanding of PD-1 and its ligands ranging from discovery to clinical significance.
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