The role of B7 costimulation in T-cell immunity

Nicola L. Harris, Franca Ronchese

Research output: Contribution to journalReview ArticleResearchpeer-review

146 Citations (Scopus)


CD4+ T cells are considered to be the major controlling element of the adaptive immune response. They recognize foreign peptides by interaction of the T cell receptor (TCR) with peptide complexed to major histocompatibility complex (MHC) class II molecules on the surface of antigen presenting cells (APC). Once activated, CD4+ T cells orchestrate the various phases of the immune response. They are responsible for the production of numerous cytokines, which activate specific immune effector cell populations including B cells, eosinophils, mast cells and macrophages. Not surprisingly, the activation of CD4+ T cells needs to be tightly regulated and is subject to finely tuned control mechanisms. The requirement for a second or 'costimulatory' signal, in addition to the antigenic signal, provides a key element for the exquisite control of T cell activation. One of the major signalling pathways responsible for delivery of this costimulatory signal is induced by interaction of CD28 on T cells with B7 molecules found only on APC. The present review outlines our current understanding of the physiological role of B7 costimulatory signals in regulating CD4+ T cell responses.

Original languageEnglish
Pages (from-to)304-311
Number of pages8
JournalImmunology and Cell Biology
Issue number4
Publication statusPublished - 16 Aug 1999
Externally publishedYes


  • B7-1
  • B7-2
  • CD28
  • Costimulation
  • Effector cell
  • Humoral immunity
  • Memory cell
  • Th1/Th2 cell

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