Immunologic Research

, Volume 28, Issue 1, pp 49–59

Cytotoxic T-lymphocyte antigen-4 and programmed death-1 function as negative regulators of lymphocyte activation

  • Laura L. Carter
  • Beatriz M. Carreno

DOI: 10.1385/IR:28:1:49

Cite this article as:
Carter, L.L. & Carreno, B.M. Immunol Res (2003) 28: 49. doi:10.1385/IR:28:1:49


The B7 family of ligands and receptors plays a critical role in the modulation of immune responses. The B7/cytotoxic T-lymphocyte antigen-4 (CTLA-4) and the more recently identified programmed death ligand/programmed death-1 (PD-L/PD-1) ligand/receptor pairs define pathways that function as rheostats of lymphocyte activation. Analysis of receptor and ligand expression patterns, as well as the phenotype of CTLA-4 or PD-1-deficient mice, strongly suggests that these pathways are nonredundant. Current data suggest that the B7/CTLA-4 pathway functions primarily to attenuate, limit, and/or terminate naïve T-cell activation in secondary lymphoid organs. The PD-L/PD-1 pathway, on the other hand, may primarily attenuate, limit, and/or terminate T-, B-, and myeloid cell activation/effector function at sites of inflammation in the periphery.

Key words

B7 ligands Cytotoxic T-lymphocyte antigen-4 Rogrammed death-1 T-cell receptor activation Costimulation 

Copyright information

© Humana Press Inc. 2003

Authors and Affiliations

  • Laura L. Carter
    • 1
  • Beatriz M. Carreno
    • 1
  1. 1.Wyeth ResearchCambridge

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