CLEC-1–deficient rats exhibit an exacerbation of in vivo DC-mediated CD4⁺Th1/Th17 responses. (A) WT, CLEC-1–deficient rats (i-ii) and chimeric rats reconstituted with BM from WT or CLEC-1–deficient rats (iii) were immunized subcutaneously in the footpad with CFA plus KLH protein (100 μg/mL). At day 10 after immunization, popliteal LNs were harvested and total LN cells or purified CD4⁺ T cells were re-stimulated in vitro with KLH or control ovalbumin (25 μg/mL) for 3 days. Histograms and representative plots of proliferation (CFSE dilution) and percentage of IL-17⁺, IL-17⁺ IFN-γ⁺, and IFN-γ⁺ cells in gated CD4⁺ T cells assessed by flow cytometry. Data were expressed as histograms as mean ± SEM of 4 independent experiments. Staining of isotypes was indicated as control. (B) WT and CLEC-1–deficient rats were transplanted with cardiac allografts. (i) At day 5 after transplantation, purified CD4⁺ T cells from spleen were re-stimulated in vitro with donor T-cell–depleted splenocytes (MLR) for 3 days. Histograms of proliferation (CFSE dilution) in gated CD4⁺ T cells assessed by flow cytometry and expressed as mean ± SEM of 4 independent experiments. (ii) Il17a and Ifng were assessed by qRT-PCR in cardiac allografts harvested at day 5 after transplantation. Results were expressed in histograms as mean ± SEM of 4 independent experiments and were expressed in AU of specific cytokine/Hprt ratio. *P < .05; **P < .01. mRNA, messenger RNA.