Figure 6. IL-4 conditioning of naïve lymphocytes alters subsequent T helper cell polarization.

(a) STAT6 phosphorylation in 4get DO11.10 TCR Tg CD4⁺ cells 18 h post-transfer into 4get mice that had been immunized with H. polygyrus larvae in the footpad 6 d before adoptive transfer. Draining and contralateral popliteal lymph nodes were analyzed. (b) Frequency of DO11.10 cells in draining popliteal lymph nodes of 4get mice injected with H. polygyrus and adoptively transferred with DO11.10 cells, as in (a), and immunized 7 days later into the same footpad with Y. pestis -pulsed DC loaded with OVA peptide (pOVA) or an irrelevant peptide control (pHA). (c) Cytokine polarization of transferred DO11.10 cells as assessed 7 d after DC immunization. IFN-γ was measured by intracellular staining following stimulation of lymph node cells for 18h in the presence or absence of OVA peptide. IL-4 expression was quantified using the 4get reporter and is shown as the frequency of GFP⁺ cells within the activated (CD44^hi) DO11.10 population. Each data point represents an individual mouse and all panels are representative of two to four independent experiments with 4 mice per group.