OVA, complete, and incomplete Freund’s adjuvant (CFA and IFA, respectively) were purchased from Sigma-Aldrich. Tissue culture media Dulbecco’s-Modified Eagle’s Medium (DMEM) was supplemented with 10% heat-inactivated fetal bovine serum (FBS), 2 mM L-glutamine, 100 U/mL penicillin, and 100 μg/mL streptomycin (all

from Gibco). Mice were immunized s.c. under ether anesthesia at two sites (base of the tail and along the back) with 100 μg of OVA in 100 μL of 1:1 PBS:CFA. Three weeks later, they were boosted s.c. with 50 μg of OVA in IFA. Arthritis was induced 2 wk after the boost, by intra-articular (i.a.) injection of 100 μg OVA in 25 μL PBS in one paw (day 1). The paw thickness was measured every day during the course of the AIA using a caliper calibrated with 0.01-mm graduations. Adoptive transfer experiments for AIA development

were performed as follows: LNCs from OVA-immunized SCH 900776 order WT mice were isolated and stimulated in vitro in the presence of OVA (20 μg/mL). To overexpress miR-21, cells were transfected with 150 nM pre-miR21 miRNA precursor (cat no. PM10206, Ambion, Austin, TX, USA) using siPORT NeoFX transfection agent (cat no. AM4511, Ambion) for the entire period of antigenic stimulation. As a negative control, OVA-stimulated cells were treated with the transfection reagent alone. After 72 h of stimulation, cells were washed and adoptively transferred (day 0) into syngeneic naïve recipients (5×106 cells/mouse). Subsequently, click here mice were immunized s.c., with OVA in incomplete Freund’s adjuvant (day 1) and 6 days later (day 7) were intra-articularly injected with OVA/PBS. The development of AIA was monitored on a daily basis as mentioned above. Mice were immunized s.c. with OVA (100 μg) in CFA as described above, and 9–10 days later, draining LNs were collected. A single-cell suspension was prepared and cells were adjusted at 4×106 cells/mL. LNs were then cultured in the presence or absence of Ag in flat-bottomed 96-well plates for 72 h at 37°C in a 10% CO2 90% air-humidified incubator. Eighteen hours before harvesting, 1 μCi of [3H]-thymidine (Amersham Biosciences) was added to each well. The cells were harvested and incorporated

radioactivity was measured using Dimethyl sulfoxide a Beckman β counter. Stimulation index (S.I.) is defined as (cpm in the presence of Ag/cpm in the absence of Ag). LN cells from WT and PD1−/− mice were isolated at days 9 and 10 after OVA immunization and restimulated in vitro with OVA (50 μg/mL). After 72 h, cells were collected and analyzed for the expression of CD4 (RM4-5), CD44 (Pgp-1, Ly24), and CD3e (145-2C11) (all from BD Pharmingen) by flow cytometry. Antibody staining was performed for 20 min at 4°C in PBS/5% FCS. Cells were acquired on a FACSCalibur (BD Biosciences) and the analysis was performed with the FlowJo software (Tree Star). Cytokine production was determined in culture supernatants harvested following 48 h stimulation of Ag-primed LNCs with OVA (20 μg/mL).