Exaggerated Th1 development by Jak3^-/- BMDCs. CD4⁺ T cells (3 × 10⁶) from OTII transgenic mice (CD45.2⁺) were injected intravenously into C57BL/6 congenic mice (CD45.1⁺). Concomitantly, wild-type and Jak3^-/- BMDCs cultured with or without OVA peptide (OVAp, 1 μM) for 2 hours were injected into footpads. Three days later, draining lymph nodes were obtained. Then cells were isolated and restimulated in vitro with anti–mouse CD28 and OVAp (1 μM). The frequency of IFN-γ–producing cells was assessed by gating on CD45.2⁺CD4⁺ cells staining for intracellular IFN-γ. Each circle indicates an individual mouse, and the mean is depicted by a horizontal line. ^**P < .001 compared with wild-type BMDCs pulsed with OVAp; n = 5.