Identification of STAT4-dependent and independent mechanisms of resistance to Toxoplasma gondii.

The capacity of IL-12 to stimulate T and NK cell production of IFN-gamma is required for resistance to Toxoplasma gondii. To identify the transcription factors involved in this mechanism of resistance, mice deficient in STAT4, a protein involved in IL-12 signaling, were infected with T. gondii and their immune responses were analyzed.

Type I interferons enhance production of IFN-gamma by NK cells.

In murine models, challenge with different viral and parasitic infection is closely associated with the production of type I interferons (IFN-alpha/beta) and NK cell production of interferon-gamma (IFN-gamma). Therefore, we wished to determine if IFN-alpha/beta had a role in the regulation of NK cell production of IFN-gamma. IFN-alpha/beta alone stimulated low levels of IFN-gamma production by purified populations of IL-2 activated NK cells but in combination with IL-12 resulted in the production of significant levels of IFN-gamma.

Biliary manganese excretion in conscious rats is affected by acute and chronic manganese intake but not by dietary fat.

We hypothesized that biliary excretion of manganese would be sensitive to acute and chronic variations in manganese and fat intakes. In the acute study, we gavaged rats with solutions containing 54Mn with either 0, 0.2, 1 or 10 mg Mn as MnCl2.