Research on the effects of CD137 signaling on the function of CD3−CD56+NK cells

ObjectiveTo investigate the effects of CD137 signaling on the regulation of CD3−CD56+NK cells function.MethodsCD3− CD56+NK cells were treated with CD137 mAb or mouse IgG1 isotype control to study the effects of CD137 signaling on the function of CD3−CD56+NK cells. Cytotoxicity was measured by LDH activity in the supernatants of cell cultures; NKG2D and LFA-1 expression on CD3−CD56+NK cells were analyzed by flow cytometry.ResultsCD137 was expressed on activated CD3−CD56+NK cells. The CD137 mAb enhanced the ability of CD3−CD56+NK cells to kill lung cancer cells(A549); Further studies revealed that the expression of NKG2D and LFA-1 was significantly increased in activated cells, and blockade of NKG2D and LFA-1 dramatically attenuated CD3−CD56+NK cytolysis of A549 cancer cells.ConclusionCD137 signaling increases the ability of CD3−CD56+NK cells to kill cancer cells via up-regulating the expression of NKG2D and LFA-1.