For LpDCs, total Lp cells after digestion with Liberase CI were passed through 70- and 40-μm cell strainers. Cells were resuspended in 1.077 g/cm3 iso-osmotic NycoPrep medium (Accurate Chemical & Scientific Corp.), and the low-density fraction was collected after centrifugation at 1,650 g for 15 min. Nycodenz gradient excludes debris and red blood cells and decreases lymphocyte numbers without changing the composition of the different subsets of LpDC (Fig. S5, available at http://www.jem.org/cgi/content/full/jem.20070663/DC1 ). Cells were washed and incubated with a mixture of mAb containing α−CD11c (HL-3), α−MHC II (AF6-120.1), α−CD16/32 (2.4G2), and α−CD103 mAb (2E7), as well as the non-DC components α−DX5 (DX5), α-NK1.1 (PK136), and α−B220 (RA3-6B2, all from eBioscience). DCs were defined as CD11c+MHCII+ cells and non-DCs were excluded when sorted by flow cytometry on a FACSVantage or FACSAria. In some experiments, CD103+ and CD103− DCs were separated. Purity was verified by flow cytometry on a FACSCalibur. I-Ab+CD11c+ cells were >90%.
For SpDCs, spleens were cut into fragments and digested by 100 mg/ml Liberase CI and 150 mg/ml DNase I, and then dissociated in Ca2+-free medium in the presence of EDTA. IAb+CD11c+ SpDCs were further purified for LpDCs, resulting in >98% purity. For phenotypic analysis, I-Ab+CD11c+ DCs were stained with fluorescent dye-conjugated α-CD11b (M1/70), α-CD103 (2E7; all from eBioscience), α-CD40 (3/23), α-CD80 (16-10A) (1 (link)), and α-CD86 (GL-1; all from BD Biosciences) mAb and analyzed by flow cytometry on a FACSCalibur or LSR II (BD Biosciences).
For SpDCs, spleens were cut into fragments and digested by 100 mg/ml Liberase CI and 150 mg/ml DNase I, and then dissociated in Ca2+-free medium in the presence of EDTA. IAb+CD11c+ SpDCs were further purified for LpDCs, resulting in >98% purity. For phenotypic analysis, I-Ab+CD11c+ DCs were stained with fluorescent dye-conjugated α-CD11b (M1/70), α-CD103 (2E7; all from eBioscience), α-CD40 (3/23), α-CD80 (16-10A) (1 (link)), and α-CD86 (GL-1; all from BD Biosciences) mAb and analyzed by flow cytometry on a FACSCalibur or LSR II (BD Biosciences).