J. Schwager et J. Schulze, INFLUENCE OF ASCORBIC-ACID ON THE RESPONSE TO MITOGENS AND INTERLEUKIN PRODUCTION OF PORCINE LYMPHOCYTES, International journal for vitamin and nutrition research, 67(1), 1997, pp. 10-16
The influence of ascorbic acid (AA) on lymphocyte functions was examin
ed in vitro and ex vivo in peripheral blood mononuclear cells (PBMC) o
f vitamin C-deficient pigs, which are unable to synthesise ascorbic ac
id. AA is accumulated to physiological levels in PBMC in vitro. The ce
ll proliferation induced by T lymphocyte mitogens was unaltered at all
AA concentrations tested (0-400 mu g/ml, i.e. 0-23 mM). Conversely, t
he response to pokeweed mitogen (PWM) which activates T and B lymphocy
tes as significantly reduced with increasing intracellular and extrace
llular AA concentrations. The response to lipopolysaccharide (LPS) sho
wed a tendency to increase at low (9 mu M) and was significantly reduc
ed at high AA concentrations (>36 mu M). The IL2 production induced by
PWM (but not by concanavalin A (Con A) or phytohemagglutinin (PHA)) d
ecreased at high AA (>142 mu M). In contrast, IL6 production induced b
y mitogens was not dependent on AA concentrations. In concordance with
these results, AA-depleted PBMC which were obtained from pigs that we
re fed an AA-free diet, displayed an increasing response to LPS and PW
M. Collectively, the data indicate that ascorbic acid selectively infl
uences the proliferation of B lymphocytes and negatively acts on IL2 p
roduction by T lymphocytes when a threshold of saturation is exceeded.