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

Objective

To investigate the effects of CD137 signaling on the regulation of CD3⁻CD56⁺NK cells function.

Methods

CD3⁻ 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.

Results

CD137 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.

Conclusion

CD137 signaling increases the ability of CD3⁻CD56⁺NK cells to kill cancer cells via up-regulating the expression of NKG2D and LFA-1.