Figure 1. Development of Tregs and immune balance. (A) Treg develops from naïve CD4 + T cell population under the influence of IL-4 and IL-2 and characterized by surface expression of CD25 and nuclear expression of FOXP3 compared to other T cell lineages. (B) Immune balance between Tregs (graft-protective cells) and T-effector cells (graft- destructive cells) modulate the effective immune response and immunotolerance to foreign