FIG. 8.

Frequencies of IFN-γ- and TNF-α-producing T cells in the spleens of Salmonella-immunized mice restimulated with LPS. The plot shows 1/the frequency of IFN-γ- and TNF-α-positive TCRβ⁺ CD4⁺ or TCRβ⁺ CD8⁺ cells in the spleens of naïve mice (open symbols) or mice who were orally immunized >15 weeks earlier with Salmonella (filled symbols) after an ex vivo restimulation with Salmonella lysate (○ or •) or with purified Salmonella LPS at the same concentration as that in the lysate (▵ or ▴). Organs were from four to seven individuals, and each symbol represents the value for an individual mouse. Specific frequencies were quantitated as described in Materials and Methods. Horizontal lines indicate the mean values for each organ.