Antigen presentation to T cells by aortic DCs. (A) Comparison between OT-1 and YA26 TCR transgenic CD8⁺ T cells. The indicated concentrations of OT-1 peptide (SIINFEKL) or CS peptide (SYVPSAEQI) were added to each T cell with or without splenic DCs. After 4 d, T cell proliferation was analyzed by CFSE dilution. (B) Presentation to OVA-specific TCR transgenic T cells. Aortic and splenic EYFP⁺ and EYFP⁻ cells were isolated from EYFP transgenic mice (n = 10) by FACS sorting. CD8⁺ OT-I and CD4⁺ OT-II cells were isolated using Dynabeads. 200 µg/ml OVA protein was added to the DC–T cell cocultures. Proliferation of OT-I and OT-II cells was evaluated by CFSE dilution on the FACS. The right shows the mean and SD of three experiments. (C) Presentation to YA26 T cells. Aortic and splenic CD11c^high CD3⁻ CD19⁻ DX5⁻ cells were isolated using FACS sorting and YA26 T cells with Dynabeads. 500 µg/ml CSP was added to the DC–T cell cocultures. Proliferation of CSP-specific TCR transgenic T cells was evaluated by CFSE dilution. The right shows the mean and SD of three experiments. (D) 5 mg OVA was injected i.v. to CD11c-EYFP (n = 10) mice. After 20 h, the aortic cell suspensions were prepared and sorted to isolate EYFP⁺ and EYFP⁻ cells. Spleen EYFP⁺ and EYFP⁻ cells were also isolated from the mice. The cells were added to OT-1 T cells at ratio of 1:3. After 3 d, T cell proliferation was analyzed by CFSE dilution. This result is representative of two independent experiments.