Identification of an alternative CTLA-4 ligand costimulatory for T cell activation

Science. 1993 Nov 5;262(5135):905-7. doi: 10.1126/science.7694361.


Stimulation of T cell proliferation generally requires two signals: The first signal is provided by the T cell receptor binding to antigen, and the second signal or costimulus is provided by a different receptor-ligand interaction. In mouse and human, the CD28-B7 interaction has been identified as a source of costimulatory signals. We have identified a cell surface molecule (GL1) that is distinct from B7 and abundantly expressed on activated B cells. On activated B cells GL1, rather than B7, is the predominant ligand for the T cell-activation molecule CTLA-4. GL1 provides a critical signal for T cell-dependent responses in vitro and in vivo.

MeSH terms

  • Abatacept
  • Animals
  • Antibodies, Monoclonal
  • Antigens, CD / metabolism
  • Antigens, Differentiation / metabolism*
  • Antigens, Surface / immunology
  • Antigens, Surface / metabolism*
  • B-Lymphocytes / immunology*
  • B7-1 Antigen / immunology
  • B7-1 Antigen / metabolism*
  • CD18 Antigens
  • CHO Cells
  • CTLA-4 Antigen
  • Cricetinae
  • Immunoconjugates*
  • Interleukin-2 / biosynthesis
  • Lymphocyte Activation*
  • Mice
  • T-Lymphocytes / immunology*


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, Differentiation
  • Antigens, Surface
  • B7-1 Antigen
  • CD18 Antigens
  • CTLA-4 Antigen
  • CTLA4 protein, human
  • Ctla4 protein, mouse
  • Immunoconjugates
  • Interleukin-2
  • Abatacept