Polyfunctional CD4⁺ T cell responses correlate with disease activity of virulent <i>Salmonella</i>.

<p>C57BL/6 mice were infected orally with 1×10⁷ virulent <i>Salmonella</i> Typhimurium and at day 14 and 21 post-infection the bacterial burden and <i>Salmonella</i>-specific CD4⁺ T cell responses were analyzed. (A) Correlation between the frequency of STM1540_262–276-specific IFN-γ⁺TNF⁺ CD3⁺CD4⁺ T cells and the recoverable <i>Salmonella</i> CFU in the spleen. (B) Correlation between the number of IFN-γ spots (as determined by ELISPOT) and the frequency of STM1540_262–276-specific IFN-γ⁺TNF⁺ CD3⁺CD4⁺ T cells. (C) Correlation between the STM1540_262–276-specific IFN-γ ELISPOTS and recoverable <i>Salmonella</i> CFU in the spleen. Data are cumulative from 12–15 <i>Salmonella</i>-infected mice analyzed at day 14 and 21 post-infection. Two independent experiments were performed at each timepoint post-infection with 3–5 mice per experiment. Correlation coefficient and significance value is indicated. Each data point represents an individual mouse.