Adoptive transfer of Treg cells improves the protective effect of CD4<sup>+</sup>Foxp3<sup>-</sup> T cells.

<p>(A) Survival curves of Rag1<sup>-/-</sup> mice infected with Pb18 after adoptive transfer of 2×10<sup>5</sup> Treg cells, 2×10<sup>6</sup> CD4<sup>+</sup>Foxp3<sup>-</sup> T cells, 2×10<sup>5</sup> Treg cells + 2×10<sup>6</sup> CD4<sup>+</sup>Foxp3<sup>-</sup> T cells, or vehicle only (<i>p</i> < 0.05 between PBS and Treg; <i>p</i> < 0.001 between PBS and CD4<sup>+</sup>Foxp3<sup>-</sup> T cells; <i>p</i> <0.001 between PBS and CD4<sup>+</sup>Foxp3<sup>-</sup> + Treg; <i>p</i> < 0.05 between Treg and CD4<sup>+</sup>Foxp3<sup>-</sup>; <i>p</i> < 0.001 between Treg and CD4<sup>+</sup>Foxp3<sup>-</sup> + Treg; n ≥ 13). (B and C) Analysis of disease severity through recovery of CFU from lungs, livers and spleens from Rag1<sup>-/-</sup> mice infected with Pb18 after adoptive transfer of 2×10<sup>5</sup> Treg cells, 2×10<sup>6</sup> CD4<sup>+</sup>Foxp3<sup>-</sup> T cells, 2×10<sup>5</sup> Treg cells + 2×10<sup>6</sup> CD4<sup>+</sup>Foxp3<sup>-</sup> T cells, or vehicle only. Horizontal bars indicate the mean value in each group (* = <i>p</i> < 0.05; ** = <i>p</i> < 0.005; *** = <i>p</i> < 0.001; n ≥ 10).</p>