http://www.jleukbio.org/cgi/rapidpdf/jlb.0706467v1.pdf "Mercury is an
important environmental pollutant and toxin, to which exposure has
been immunosuppressive, leading to autoimmune and allergic
manifestaions...In our studies, we have used concentrations of 20 ng/
ml or lower, which is readily achievable during childhood
vaccinations".
Thimerosal induces TH2 responses via influencing cytokine secretion by
human dendritic cells.Agrawal A, Kaushal P, Agrawal S, Gollapudi S,
Gupta S.
Division of Basic and Clinical Immunology, University of California,
Irvine, CA 92697, USA. [email hidden]
Thimerosal is an organic mercury compound that is used as a
preservative in vaccines and pharmaceutical products. Recent studies
have shown a TH2-skewing effect of mercury, although the underlying
mechanisms have not been identified. In this study, we investigated
whether thimerosal can exercise a TH2-promoting effect through
modulation of functions of dendritic cells (DC). Thimerosal, in a
concentration-dependent manner, inhibited the secretion of LPS-induced
proinflammatory cytokines TNF-alpha, IL-6, and IL-12p70 from human
monocyte-derived DC. However, the secretion of IL-10 from DC was not
affected. These thimerosal-exposed DC induced increased TH2 (IL-5 and
IL-13) and decreased TH1 (IFN-gamma) cytokine secretion from the T
cells in the absence of additional thimerosal added to the coculture.
Thimerosal exposure of DC led to the depletion of intracellular
glutathione (GSH), and addition of exogenous GSH to DC abolished the
TH2-promoting effect of thimerosal-treated DC, restoring secretion of
TNF-alpha, IL-6, and IL-12p70 by DC and IFN-gamma secretion by T
cells. These data suggest that modulation of TH2 responses by mercury
and thimerosal, in particular, is through depletion of GSH in DC.