B7x: A widely expressed B7 family member that inhibits T cell activation

Xingxing Zang, P'Ng Loke, Jayon Kim, Kenneth Murphy, Rebecca Waitz, James P. Allison

Research output: Contribution to journalArticlepeer-review

345 Scopus citations


B7 family proteins provide costimulatory signals that regulate T cel responses. Here we report the third set of B7 family-related T cel inhibitory molecules with the identification of a homolog of the B7 family, B7x. It is expressed in immune cells, nonlymphoid tissues, and some tumor cell lines. B7x inhibits cell-cycle progression, proliferation, and cytokine production of both CD4+ and CD8+ T cells. B7x binds a receptor that is expressed on activated, but not resting T cells that is distinct from known CD28 family members. Its receptor may be a recently identified inhibitory molecule, B and T lymphocyte attenuator. These studies identify a costimulatory pathway that may have a unique function in down-regulation of tissue-specific autoimmunity and antitumor responses.

Original languageEnglish (US)
Pages (from-to)10388-10392
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number18
StatePublished - Sep 2 2003
Externally publishedYes


  • Autoimmunity
  • Costimulation
  • Tumos

ASJC Scopus subject areas

  • General


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