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 microM 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 microM 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 microM 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 microM arginine, HS did not restore Jurkat cell proliferation that had been suppressed by PGE(2). Increased concentrations of arginine in the media increased MTT cell proliferation. In 800 microM arginine media, HS restored PGE(2)-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 microM arginine. HS restored PGE(2)-suppressed Jurkat cell proliferation even though HS was added at 2 h after PGE(2) stimulation.