Induction of class II antigens of pDCs detected by immunofluorescence and molecular analysis after CD2 ligation. CD14⁺ Mx's were precultured for 36 hours in 10% PHS, followed by anti-T11₂ enrichment of pDCs. The enriched pDCs were resuspended in fresh 10% PHS at a final concentration of 10⁶ cells per milliliter for 12 additional hours in the presence of an IR control (B) or anti-T11₃ (C). Afterward, 2-color analysis of each DC sample was performed with anti–HLA-DR and -DQ mAbs. The quadrant boundaries were set using isotype controls (A). RT-PCR (D) was used to assess HLA-DP, HLA-DM, and β-actin gene expression of pDCs that were cultured in the presence of either anti-T11₂ and IR control or anti-T11₂ and anti-T11₃ mAbs. The results are representative of 3 or more studies. Percentages in panels A-C indicate the percentage of cells expressing antigen in that quadrant.