(Journal Article): The B7 family revisited.
 
Greenwald RJ, Freeman GJ, Sharpe AH (Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA., rgreenwald@rics.bwh.harvard.edu )
 
IN: Annu Rev Immunol 2005; 23(1):515-548
Impact Factor(s) of Annu Rev Immunol: 47.4 (2005), 52.431 (2004), 52.28 (2003), 54.455 (2002), 46.233 (2001)

Fulltext:    HTML  PDF

ABSTRACT: The discovery of new functions for the original B7 family members, together with the identification of additional B7 and CD28 family members, have revealed new ways in which the B7:CD28 family regulates T cell activation and tolerance. B7-1/B7-2:CD28 interactions not only promote initial T cell activation but also regulate self-tolerance by supporting CD4+CD25+ T regulatory cell homeostasis. CTLA-4 can exert its inhibitory effects in both B7-1/B7-2 dependent and independent fashions. B7-1 and B7-2 can signal bidirectionally by engaging CD28 and CTLA-4 on T cells and by delivering signals into B7-expressing cells. The five new B7 family members, ICOS ligand, PD-L1 (B7-H1), PD-L2 (B7-DC), B7-H3, and B7-H4 (B7x/B7-S1) are expressed on professional antigen-presenting cells as well as on cells within nonlymphoid organs, providing new means for regulating T cell activation and tolerance in peripheral tissues. The new CD28 families members, ICOS, PD-1, and BTLA, are inducibly expressed on T cells, and they have important roles in regulating previously activated T cells. PD-1 and BTLA also are expressed on B cells and may have broader immunoregulatory functions. The ICOS:ICOSL pathway appears to be particularly important for stimulating effector T cell responses and T cell-dependent B cell responses, but it also has an important role in regulating T cell tolerance. In addition, the PD-1:PD-L1/PD-L2 pathway plays a critical role in regulating T cell activation and tolerance. In this review, we revisit the roles of the B7:CD28 family members in regulating immune responses, and we discuss their therapeutic potential.

TYPE OF PUBLICATION: Review

Articles citing this article:

• Yadav D, Sarvetnik N. Costimulation and Pancreatic Autoimmunity: The PD-1/PD-L Conundrum. Rev Diabetic Stud 2006. 3: 6-10.
  » Diabetes OD » Development and Function of Pa... » Immune System » Activation and Inhibition » Costimulation » Programmed Death » Journal Article