Specific T cell populations have suppressive/regulatory cells known as Regulatory T-cell or Tregs (Previously known as suppressor T-cell). Among them CD4+ regulatory T cells (Tregs) basically has two different subsets Tr1 and Th3 cells which are differentiated by their distinct suppressive mechanisms. The thymus-derived Tregs or natural Tregs (nTregs) express CD4 and high CD25 with FOXP3 (Forkhead Box-P3) to be a key regulatory gene (Ref.1). Apart from these, other markers of Treg include CTLA4 (Cytotoxic T-Lymphocyte-Associated protein-4), GITR (Glucocorticoid-Induced TNFR-Related protein) and LAG-3 (Lymphocyte Activation Gene-3). Treg cells are implicated in the development of autoimmunity, allergy and rejection of organ transplants, as well as the suppression of immune responses to cancer. Down regulation of the antigen presentation machinery has been [...]