CD8α⁺ and CD8α⁻ DCs prime distinct Th cells in vivo. LN cells from mice injected with either subset or a combination (at a proportion of 1 CD8α⁺ to 10 CD8α⁻) 5 d earlier were cultured without antigen or with 50 (a) or 10 (a–f) μg/ml KLH. Some mice were injected with 1 mg anti-CD4 mAbs before priming. Proliferation and lymphokine production were measured as indicated in Materials and Methods. Figure summarizes the results (mean ± SD) obtained in five independent experiments.