Figure 6. Blockade of IL-6R signaling does not prevent iTreg reversion but increases Thy1.2⁺ cell numbers.

(A-C) Lethally irradiated Balb/c mice were transplanted with B6.PL BM, B6.PL spleen cells (adjusted to yield 0.6 × 10⁶ αβ T cells) and 0.6 × 10⁶ B6 in vitro-differentiated iTregs. Mice were then administered anti-IL-6R (n=11) or isotype control (n=9) antibody on days 0 and 7 as described in Methods. Data are cumulative results of three experiments. (A) Representative dot plots gated on CD4⁺ T cells showing the percentage of Thy1.2⁺ cells that expressed EGFP in spleen, liver, lung, and colon samples 10 days after transplantation. (B) Absolute number of CD4⁺ Thy1.2⁺ EGFP⁺ and EGFP⁻ cells in the specified tissue sites from animals treated with isotype (black bars) or anti-IL-6R antibody (white bars). (C) Percentage of CD4⁺ Thy1.2⁺ EGFP⁻ cells that secreted IFN-γ in each tissue. (D) Representative histograms showing IL-6R expression on naïve CD4⁺ T cells (solid line) and in vitro-differentiated iTregs (dashed line) prior to transplantation. Isotype control is in gray. (E). IL-6R expression on iTregs obtained from the spleen of mice ten days post transplantation. Isotype control is in gray. Statistics: * p<0.05, **p<0.01.