The B7–CD28 superfamily

@article{Sharpe2002TheBS,
  title={The B7–CD28 superfamily},
  author={Arlene H. Sharpe and Gordon J. Freeman},
  journal={Nature Reviews Immunology},
  year={2002},
  volume={2},
  pages={116-126}
}
The B7-1/B7-2–CD28/CTLA-4 pathway is crucial in regulating T-cell activation and tolerance. New B7 and CD28 molecules have recently been discovered and new pathways have been delineated that seem to be important for regulating the responses of previously activated T cells. Several B7 homologues are expressed on cells other than professional antigen-presenting cells, indicating new mechanisms for regulating T-cell responses in peripheral tissues. Some B7 homologues have unknown receptors… 
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