Identification of CD200R3 as a specific molecule for BM-DC_regs. (A-C) The transcriptional expression of Cd200rs in BM-DCs (A,B) and leukocytes (C) was measured by RT-PCR (A,C) and real-time PCR (B). The results of RT-PCR for Actb demonstrate the loading of equal amounts of DNA on the gel (A,C). The expression of Cd200rs determined by real-time PCR was normalized to that of Actb, and the data are as the comparative fold increase compared with BM-mDCs (B). (D) The expression of cell surface molecules on BM-DCs was analyzed by flow cytometry, and data are represented by a dot plot and a histogram. Data are representative of 4 replicate experiments (A-D). (E) Rag2^−/−KJ1-26⁺ T cells (5 × 10⁴) were cultured with the indicated BM-DCs (5 × 10³) in the presence or absence of anti-CD200R3 mAb or control Ig (each 5 μg/mL) for 3 days, and the proliferative response was measured. *P < .01 compared with each of the BM-DCs alone. Data are mean ± SEM, and the results are combined from 4 replicate experiments.