ABSTRACT
The effect of vitamin C on T lymphocyte function is not clear. In-vivo supplementation of vitamin C is found to have a stimulatory effect on T cells while studies in which ascorbic acid was added to T cell cultures show an inhibition of cell function. The study aims to investigate the effect of ascorbic acid on interleukin- 2 secretion by T cells in whole blood cultures which better resembles the physiological environment than pure T cell cultures. It was found that ascorbic acid, when added to whole blood cultures at a very high concentration of 1 mM, inhibits interleukin-2 secretion by T cells (p<0.05). However at lower concentrations of 0.25 mM and 0.5 mM significant inhibition was not seen which is contrary to earlier reports in pure T cell cultures. Hence it can be concluded that ascorbic acid inhibits T cell function in-vitro at high concentrations but the effect is relatively less in whole blood cultures compared to pure T cell cultures.
ABSTRACT
Voltage gated potassium channels present in T lymphocytes play an important role during lymphocyte activation. Though an increase in potassium currents has been reported in activated lymphocytes, changes in potassium currents in culture without activation by antigen or mitogen has not been reported. The peak potassium current densities on day 1 and day 5 of culture have been compared in this study. Peripheral blood mononuclear cells (PBMCs) were separated by density gradient centrifugation. Lymphocytes were separated from PBMCs by negative selection using anti-CD14 coated magnetic beads and cultured under appropriate conditions without antigenic or mitogenic stimulation. Lymphocytes were patched on day 1 or day 5 of culture. Voltage gated potassium currents were recorded by whole cell patch clamp technique using a depolarizing protocol. The mean of peak current densities recorded at +60 mV on day 1 of culture was 228.12± 89.39 pA/pF (n=7) and on day 5 of culture was 468.96 ± 192.07 pA/pF (n=7). The difference between the current densities on day 1 and day 5 was found to be significant. Change in electrophysiological characteristics can lead to functional changes in the lymphocytes and this should be considered when culturing lymphocytes in vitro for research and clinical use.