expert reviews
http://www-ermm.cbcu.cam.ac.uk
a Professional APC
(e.g. dendritic cell)
MHC
TCR
Signal 1
T-cell activation
CD28
CD80 (B7.1)
[or CD86 (B7.2)]
Signal 2
b Non-professional APC
(e.g. resting B cell)
Signal 1
Signal 1
T-cell anergy
No signal 2 or costimulation
because of lack of B7
on the APC
The role of signals 1 and 2 in T-cell activation
Expert Reviews in Molecular Medicine c 2000 Cambridge University Press
Figure 2. The role of signals 1 and 2 in T-cell activation. ‘Professional’ APCs, such as dendritic cells,
provide more-effective costimulation (signal 2) and, therefore, efficently activate T cells. By contrast, even
though ‘non-professional’ APCs, such as B cells or activated endothelial cells, can provide signal 1, they
are less efficient at providing signal 2 and are more likely to induce anergy. Abbreviations used: APC,
antigen-presenting cell; MHC, major histocompatibility complex; TCR, T-cell receptor (fig002mhb).
Accession information: (00)00216-7a.pdf (short code: fig002mhb); 27 November 2000
ISSN 1462-3994 ©2000 Cambridge University Press
The role of signals 1 and 2 in T-cell activation
in molecular medicine
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