galectin-1, is overexpressed in regulatory T cells, and that expression is increased after activation. Most importantly, blockade of galectin-1 binding significantly reduced the inhibitory effects of human and mouse CD4 CD25 T cells. Reduced
regulatory activity was observed in CD4, CD25 Tcells obtained from galectin-1– homozygous null mutant mice. These results
suggest that galectin-1 is a key effector of the regulation mediated by these cells. (Blood. 2007;109:2058-2065)