1. Dendritic cells: regulators of hepatic immunity or tolerance?
Derek G Doherty, Cliona O'Farrelly 
Journal of Hepatology 
Volume 34, Issue 1, Pages (January 2001)
DOI: /S (00)

2. Fig. 1
Molecular interactions that mediate naı̈ve T lymphocyte activation by professional antigen presenting cells (APCs). Antigen recognition is mediated by ligation of the T cell receptor (TCR) and the CD4 or CD8 coreceptor with a peptide/major histocompatibility complex (MHC) on the surface of the APC. Costimulation of T cell activation generally involves the ligation of CD28 on the T cell with CD80 (B7-1) or CD86 (B7-2) on the APC. Ligation of the TCR is associated with upregulation of CD154 expression by the T cell which binds to CD40 on the APC, thereby increasing expression of CD80 and CD86. Non-specific interactions between the adhesion molecules CD54 (intracellular adhesion molecule-1 or ICAM-1) on the APC and CD11a/CD18 (lymphocyte function antigen-1 or LFA-1) on the T cell and between CD58 (LFA-3) on the APC and CD2 on the T cell strengthen the physical association between the two cells. T cell activation results in the upregulation of cytotoxic T lymphocyte antigen-4 (CTLA-4) which competes with CD28 for CD80 and CD86 binding and downregulates T cell activation. Antigen-specific interactions with APCs lacking costimulatory or adhesion molecules can result in inactivation of naı̈ve T cells by anergy, whereas effector T cells have do not need costimulation for their activation.
Journal of Hepatology  , DOI: ( /S (00) )