Response to vaccinia infection in the presence of rsTreg. [BALB/c × C57BL/6]F1 recipient mice were lethally irradiated and then grafted with 3 × 10⁶ CD3ε^−/− BM cells (BM only □) and 3 × 10⁶ allogeneic Ly5.1⁺ C57BL/6 T cells with 3 × 10⁶ specific rsTreg (Tallo+rsTreg ▴, , and ). Nonmanipulated mice represent the control group (n.m. ○). At 4 months postreconstitution mice were infected intranasally with 5 × 10⁴ plaque-forming units (PFU) of vaccinia virus and (A) body weight loss was determined at different time points postinfection up to day 16. Symbols represent the mean value and bars are the SD. (B) Absolute number of Ly5.1⁺ CD4⁺ and CD8⁺ T cells and B cells in the spleen, at day 21 postinfection, is indicated for Tallo+rsTreg mice (▴). As a control, a Tallo+rsTreg group was not infected with vaccinia. and , in infected Tallo+rsTreg group, represent spleens that were tested in ELISPOT. (C) Elispot for the production of IFNγ by splenocytes was done at day 21 postinfection on splenocytes. In the Tallo+rsTreg group infected with vaccinia, high and low IFNγ producers were identified by and , respectively. As a control, a Tallo+rsTreg (▴) group was not infected with vaccinia. Each symbol represents an individual mouse and the horizontal bars are the means. Data were combined from 2 independent experiments with 2 to 7 mice per group per time point. *P < .05.