Aim: To investigate the effect of N-methyl-D-aspartate (NMDA) receptor antagonist on T helper (TH) cell differentiation and intracellular transcriptional factors in vitro.

Methods: Ten male healthy volunteers (aged 20-45 y, BMI 18-25) were enrolled in this study. Twenty milliliters peripheral blood was collected in the morning from fasted volunteers and peripheral blood mononuclear cells (PBMC) were isolated. PBMC were incubated with phorbol-myristate-acetate (25 ng/ml) (PMA) plus ionomycin (1 μg/ml) in the presence of ketamine or MK-801 at 37 °C. TH subsets, supernatant interferon γ (IFN-γ), interleukin 4 (IL-4), and intracellular transcriptional factors T-bet and GATA3 were analyzed 4 h later.

Results: The number of TH0 cells was kept constant and at baseline before PMA and ionomycin stimulation in each group. TH1 cells, TH2 cells, IFN-γ and IL-4 levels were significantly increased after PMA and ionomycin stimulation. Ketamine and MK-801 decreased TH1 cells, TH2 cells, IFN-γ and IL-4 levels but increased the ratio of TH1/TH2 and IFN-γ/IL-4 in the presence of PMA and ionomycin. Ketamine or MK-801 alone had no effect on either of them. T-bet and GATA3 activities in PBMC were significantly increased after PMA and ionomycin stimulation. Ketamine and MK-801 decreased T-bet and GATA3 activities but increased the ratio of T-bet/GATA3 following PMA and ionomycin stimulation. Ketamine or MK-801 alone had no effect on the activity of T-bet, GATA3 or T-bet/GATA3.

Conclusion: NMDA antagonist can suppress TH cell differentiation and subsequent cytokines production but increase TH1/TH2 ratio following PMA and ionomycin stimulation, it may be related to its regulation on T-bet and GATA3 activities.