Abstract:

Objective    To research effects of GABA and GABAA receptor antagonist (picrotoxin, PTX) on proliferation, surface receptor expression and cytotoxicity of human peripheral blood γδT cells, and possible mechanism of action. Methods    After γδT cells were treated with different concentrations of GABA and PTX, the proliferation, surface receptor expression and cytotoxicity of γδT cells were detected by MTT, flow cytometry and the lactate dehydrogenase method, respectively. Results    GABA could decrease proliferation of γδT cells(P＜0.01) in a dose-dependent manner. Expression of NKG2D on γδT cells was down-regulated by GABA, while TCR-γδ was up-regulated. GABA could inhibit γδT cells from killing the human pancreatic cancer cell line SW1990. PTX had an antagonistic role in the actions of GABA on the proliferation and cytotoxicity of γδT cells, but for surface receptor expression, PTX had a slightly synergistic effect. Conclusion     GABA may affect γδT cells via multiple pathways, besides its a receptor. The cytotoxicity of γδT cells is mainly mediated by NKG2D, which may need expressions of both γδTCR and NKG2D.

Key words: γ-aminobutyric acid；  Picrotoxin； γδT cells； Cytotoxicity