For functional assays, mouse anti-human CD3 (HIT3a) and anti-human CD28 (CD28.2) were purchased from BD Biosciences. For ELISPOT assays, mouse anti-human IFN-γ capture mAbs and a biotinylated anti-human see more IFN-γ mAbs were purchased from Fisher Scientific (Pierce Biotechnology, Rockford, IL); mouse anti-human IL-2 capture mAbs, biotinylated anti-human IL-2 mAbs and recombinant IL-2 were purchased from

R&D Systems. Pooled human AB serum was purchased from Pel Freeze Biologicals (Rogers, AR). Rapamycin was gifted to the laboratory by Wyeth-Ayest Research (Princeton, NJ) and CsA was purchased from Novartis Pharmaceuticals (East Hanover, NJ). Human peripheral blood was obtained from healthy volunteers consented in accordance with IRB approval by Children’s Hospital Boston. CD4+ T cells were isolated from PMBCs using magnetic beads (Dynal CD4 Positive Isolation Kit, Invitrogen, selleck screening library Carlsbad, CA) according

to the manufacturer’s instructions. The purity of isolated CD4+ cells was found to be >97% by FACS. For depletion studies, purified CD4+ T cells were incubated for 20 min with 1 μg per 106 target cells of anti-CXCR3 mAbs (1C6, BD Biosciences) or anti-CD25 mAbs (M-A251, BD Biosciences) at 4°C, and were washed in PBS/0.5% BSA. The cells were subsequently incubated with Pan mouse IgG magnetic beads (Dynal Cellection Kit, Invitrogen) and CXCR3+ or CD25+ cells were removed

by magnetic separation. The purity of the depleted populations was >92% as assessed by flow cytometry. For migration assays, CD4+CD25+CD127dim/− cells were isolated from PBMCs using magnetic beads (Miltenyi Biotec) and were FACS-sorted (using 1C6, BD Biosciences) into CXCR3+ and CXCR3neg populations. Cell culture was performed at 37°C in 5% CO2 in RPMI 1640 media (Cambrex, Charles City, IA) containing 10% human AB serum, 2 mM L-glutamine, 100 U/mL penicillin/streptomycin (Gibco-Invitrogen), 1% sodium bicarbonate and 1% sodium pyruvate (Cambrex) in Histamine H2 receptor 96-well, round-bottom plates (Corning Life Sciences, Lowell, MA). Mitogen-dependent assays were performed in 96-well round bottom cell culture plates in triplicate wells (1×105 T cells/well) in a final volume of 200 μL. The cells were stimulated with either immobilized anti-CD3 mAbs (5 μg/mL) alone or with immobilized anti-CD3 mAbs in combination with soluble anti-CD28 mAbw (1 μg/mL) for 3 days. Mixed lymphocyte reactions were performed using 2×105 responders and γ-irradiated PBMCs (1700 rad) as stimulators in a ratio of 1:1. Cells were cultured in triplicate wells using either allogeneic or autologous stimulators. Proliferation was assessed after 5 days by 3H–Thymidine (Perkin Elmer, Boston, MA; 1 μCi/well) incorporation for the final 18 h of culture, and data were analyzed using suppression ratios.