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

Abstract

Background. Hypertonic saline (HS) restores prostaglandin E-2 (PGE(2))-induced T-cell suppression in the presence of 1100 mu M arginine. However, under arginine-free culture conditions, HS dose not restore T-cell proliferation. Therefore, we wanted to determine if HS can restore PGE(2)-induced T-cell suppression in the presence of 80 mu M of arginine, the physiologically relevant arginine concentration. We also wanted to determine the concentration of arginine that induces HS restoration of PGE(2)-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 mu M arginine. In both the PGE(2)-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 mu M 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 mu M arginine media, HS restored PGE2-suppressed Jurkat cell proliferation to normal. HS restored PGE(2)-suppressed Jurkat cell proliferation when it was added at 2 h, similar to at same time and 1 h after PGE(2) stimulation. Conclusions. In order to restore PGE(2)-suppressed Jurkat cell proliferation, HS requires at least 800 mu M arginine. HS restored PGE(2)-suppressed Jurkat cell proliferation even though HS was added at 2 h after PGE(2) stimulation. (C) 2010 Elsevier Inc. All rights reserved.