The role of B7 costimulation in T-cell immunity

Immunol Cell Biol. 1999 Aug;77(4):304-11. doi: 10.1046/j.1440-1711.1999.00835.x.


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.

Publication types

  • Review

MeSH terms

  • Abatacept
  • Animals
  • Antibody Formation
  • Antigens, CD / chemistry
  • Antigens, CD / genetics
  • Antigens, CD / metabolism*
  • Antigens, Differentiation / metabolism
  • B7-1 Antigen / chemistry
  • B7-1 Antigen / genetics
  • B7-1 Antigen / metabolism*
  • B7-2 Antigen
  • CD28 Antigens / chemistry
  • CD28 Antigens / genetics
  • CD28 Antigens / metabolism
  • CTLA-4 Antigen
  • Humans
  • Immunoconjugates*
  • Immunologic Memory
  • Lymphocyte Activation
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Mice
  • Models, Biological
  • T-Lymphocytes / immunology*
  • Th1 Cells / immunology
  • Th2 Cells / immunology


  • Antigens, CD
  • Antigens, Differentiation
  • B7-1 Antigen
  • B7-2 Antigen
  • CD28 Antigens
  • CD86 protein, human
  • CTLA-4 Antigen
  • CTLA4 protein, human
  • Cd86 protein, mouse
  • Ctla4 protein, mouse
  • Immunoconjugates
  • Membrane Glycoproteins
  • Abatacept