Figure 4.

Stat6-independent production of IL-4 by T-CD4 T cells. (A) Mixed BM chimeras. BM from Stat6^−/− mice were mixed with those from WT or CIITA^Tg mice and cotransferred into B6 or Aβ^−/− recipients. Splenic CD4 T cells from mixed BM chimeras were differentiated into Th1 or Th2 cells. Before fixation and permeabilization, Th cells were stained with an anti-CD45.2 mAb to distinguish T cells derived from Stat6^−/− BM (CD45.1⁺) as opposed to those from Stat6^+/+ BM (CD45.2⁺). Cytokine production profiles were subsequently assayed by ICS. Mice were analyzed 10 wk after BM transplantation. The percentage of positive cells in each quadrant is shown. (B) Co-culturing Stat6^−/− CD4 T cells with CIITA^Tg CD4 T cells during in vitro Th cell differentiation is not sufficient to induce IL-4 expression. Histograms show IL-4 production profiles of Stat6^+/+ WT or CIITA^Tg cells (CD45.1⁺), or Stat6^−/− cells (CD45.2⁺) in the co-cultures. The percentage of positive cells in each gate is shown.