Hybrid Th1/2 memory cells stably maintain their key transcription factor and cytokine profile.

<p>(A–B) LCMV-TCR^tg Thy1.1⁺ Th1, Th2, or hybrid Th1/2 cells were generated <i>in vitro</i> for 2 wk and transferred into WT C57BL/6 mice (<i>n</i> = 3–8 mice/group). Data are representative of two independent experiments. (A) T-bet and GATA-3 expression in CD4⁺Thy1.1⁺ cells from peripheral blood was analyzed in a kinetic fashion and plotted as geometric mean indices ± SD. Dot plot depicts a representative staining on d 76 after transfer. (B) Splenocytes were restimulated with GP_64–80 peptide on d 42 after transfer and cytokine production of CD4⁺Thy1.1⁺ donor cells was analyzed. Numbers indicate frequencies. (C–F) WT C57BL/6 mice were infected with <i>H. polygyrus</i> and cured with Pyrantel at the peak of infection on d 21 (<i>n</i> = 10). Data are representative of two independent experiments. (C) T-bet and GATA-3 expression was determined in CD4⁺ cells from peripheral blood in a kinetic fashion and plotted as geometric mean indices ± SD. Dot plot (right panel) depicts a representative staining on d 30 after cure. Numbers indicate frequencies. The blue, red, and violet frames in this inset also document the gating strategy for Th1, Th2, and hybrid Th1/2 cells, respectively, which are shown in panels (C), (D), and (F). (D) Cytokine expression upon restimulation with PMA/ionomycin was analyzed in CD4⁺ cells from spleens of <i>H. polygyrus</i>–infected mice on d 63 after cure. Numbers indicate frequencies. (E) Output of <i>H. polygyrus</i> eggs was determined one day before and 4 d after treatment with Pyrantel. (F) Frequencies ± SD of T-bet⁻GATA-3⁺ (Th2) and T-bet⁺GATA-3⁺ (hybrid Th1/2) CD4⁺ cells in the peripheral blood are depicted over time after cure from <i>H. polygyrus</i> infection.