T suppressor cells alter certain antigen presenting cell activities thought to be central to the prevention of autoimmune diseases, allergies, transplant rejection and immune-deficiency disorders, but the molecular basis that underlies this mechanism remains unclear. In January 28 online Nature Immunology, Chih-Chao Chang and colleagues from Columbia University, New York, show that the immunoglobulin-like transcript 3 (ILT3) and ILT4 inhibitory receptors have an important role in the tolerization of dendritic cells by T suppressor cells.

Chang et al. generated allospecific human T cell lines and found that CD8⁺CD28^- alloantigen-specific T suppressor (TS) cells induce the up-regulation of ILT3 and ILT4 receptors on monocytes and dendritic cells, rendering these antigen-presenting cells (APCs) tolerogenic. In addition, tolerogenic APCs showed reduced expression of costimulatory molecules and induced antigen-specific unresponsiveness in CD4⁺ T helper cells (Nat Immunol 2002, DOI: 10.1038/ni760).

"The data we present here suggest...