Concentration of Arginine and Optimal Time of Hypertonic Saline in Restoration of T-Cell Dysfunction

Background: Hypertonic saline (HS) restores prostaglandin E2 (PGE2)-induced T-cell suppression in the presence of 1100 μM arginine. However, under arginine-free culture conditions, HS dose not restore T-cell proliferation. Therefore, we wanted to determine if HS can restore PGE2-induced T-cell suppression in the presence of 80 μM of arginine, the physiologically relevant arginine concentration. We also wanted to determine the concentration of arginine that induces HS restoration of PGE2-suppressed T-cell proliferation and whether HS restoration of T-cell dysfunction is dependent on the injection time of HS. Materials and Methods: Jurkat cells were cultured in media containing 0, 40, 80, 400, 800, or 1100 μM arginine. In both the PGE2-stimulated and HS-treated group, we measured cell proliferation using MTT assay and arginase activity. We also measured cell proliferation relative to HS injection time. Results: In 80 μM arginine, HS did not restore Jurkat cell proliferation that had been suppressed by PGE2. Increased concentrations of arginine in the media increased MTT cell proliferation. In 800 μM arginine media, HS restored PGE2-suppressed Jurkat cell proliferation to normal. HS restored PGE2-suppressed Jurkat cell proliferation when it was added at 2 h, similar to at same time and 1 h after PGE2 stimulation. Conclusions: In order to restore PGE2-suppressed Jurkat cell proliferation, HS requires at least 800 μM arginine. HS restored PGE2-suppressed Jurkat cell proliferation even though HS was added at 2 h after PGE2 stimulation. [ABSTRACT FROM AUTHOR]