CD27 Ligand, which belongs to the TNF superfamily, is a type II transmembrane protein. Like NK cells, CD27L is also located in activated T and B lymphocytes. Along with NK enhancement, CD27L and its receptor regulate the immune response by raising expansion and differentiation of T cell. CD27 signaling can act like a co-stimulatory effector to sustain survival of the CD8+ T cells, mainly by increasing expression of the IL-2 gene.