Attenuated CD4⁺ and CD8⁺ T-cell stimulation in mDia1^−/− BMDCs. (A-D) OT-II CD4⁺ T-cell stimulation by DCs. B6 and mDia1^−/− mice were injected with CFA in the presence or absence of OVA, and CFSE-labeled OT-II CD4⁺ T cells were transferred intravenously. Forty-eight hours later, skin-draining popliteal and inguinal LN cells were collected and stained with CD4. Flow cytometry profiles (A), histograms of CFSE⁺ CD4⁺ cells (B), the numbers of CD4⁺ T cells per draining LNs in each division (C), and the numbers of CD69⁺ activated T cells (D) per draining LNs are shown. The numbers indicated in A are the ratio (%) of CD4⁺ CFSE⁺ cells (right) and CD4⁺ CFSE⁻ cells to total cells. The numbers indicated in panel B are the ratio of each fraction to CD4⁺ CFSE⁺ cells. (E) IFN-γ mRNA expression was evaluated through quantitative reverse-transcribed polymerase chain reaction analysis. (F) OT-I CD8⁺ T-cell stimulation by DCs. CFSE-labeled OT-I CD8⁺ T cells were transferred intravenously to mice that had been pretreated as described in panels A to E, and the distribution of cell numbers in draining LNs is shown. (G) DTH induced by injection with OVA plus CFA. B6 and mDia1^−/− mice were sensitized with OVA in CFA subcutaneously at the front footpads and challenged with OVA in CFA in the hind footpads. B6 and mDia1^−/− mice that had not received OVA sensitization were used as negative controls. Footpad thickness change over 48 hours is shown. S indicates sensitization; and C, challenge. (H) DTH induced by OVA-pulsed BMDCs. We injected B6 or mDia1^−/− BMDCs pulsed with (BMDC⁺) or without (BMDC⁻) OVA into the front footpads and challenged the mice by injecting OVA in CFA into the hind footpads. Administration of B6 BMDCs not pulsed with OVA during sensitization was used as a negative control. Footpad swelling data over 24 hours and 48 hours after challenge with OVA in CFA are shown. Data are mean ± SD and are representative of 3 independent experiments with similar results.