In vitro effects of vanadate on human immune functions.

Vanadium (V) is an element with wide industrial applications and environmental release. The object of this study was to determine the in vitro effects of high (10(-4) M) and low (10(-7) M) concentrations of sodium metavanadate (NaVO3) on cultured peripheral blood mononuclear cell (PBMC) proliferation, cytokine release, CD expression, and granulocyte O2- production. At 10(-4) and 10(-7) M, NaVO3 did not modify PBMC proliferation in the absence of phytohemagglutinin (PHA). On the other hand, 10(-4) M NaVO3 reduced by -25% the PBMC proliferation in PHA-stimulated cultures, with a significant reduction of the stimulation index (SI) of blastogenesis. Moreover, 10(-4 M NaVO3 significantly reduced the release of IFN-gamma by PHA-stimulated PBMCs, and 10(-7) M NaVO3 significantly enhanced the release of TNF-alpha. In addition, IL-5 release was significantly inhibited by high concentration of sodium metavanadate and significantly enhanced by low concentration of NaVO3. Neither 10(-4) nor 10(-7) M NaVO3 modified the expression of CD3+, CD4+, CD8+, or CD56+ in PHA-stimulated and unstimulated lymphocytes. Finally, 10(-4) M NaVO3 reduced the granulocyte production of O2- by about 70%, while 10(-7) vanadate reduced its production to a lesser extent. These results show that 10(-4) M NaVO3 exerts inhibitory effects on PBMCs, while at 10(-7) M it exerts a stimulatory action with a slight shift of the immune response towards a Th2-type response. This investigation suggests that environmental V can have important effects on the human immune system.