Since transgenic mouse tools for Treg manipulation based on Foxp3-expression are available primarily on the susceptible, Nramp1-defective C57BL/6 background, we sought to exploit the autosomal dominant resistance to Salmonella conferred by wild-type Nramp1, and the X-linked inheritance of Foxp3 transgenic mice by examining infection in resistant F1 129SvJ X C57BL/6 mice [30]. Here, FOXP3 is linked to infection.