Purified protein was quantified using Coomassie Plus Protein Assay Reagent (Pierce). The plasmid pCI-EαRFP was prepared by PCR cloning of the EαRFP coding

sequence from the previously described plasmid pTrcHisEαRFP [1] into the mammalian expression plasmid pCIneo (Promega). The plasmid pCI-EαGFP was created by PCR using pTrcHisEαGFP as template. The plasmid pCI-OVAeGFP expresses a cytosolic OVAeGFP fusion protein. HeLa cells were cultured in DMEM supplemented as described above and were transfected using Lipofectamine 2000 (Invitrogen) according to the manufacturer’s instructions. To ensure that pCI-EαGFP- and pCI-EαRFP-expressed EαGFP and EαRFP proteins could be correctly processed and the Eα peptide surface displayed, we set up co-culture, cross-presentation assays using Ipatasertib transfected HeLa cells as a source of Eα antigen and B6 (I-E−/I-Ab+) BMDCs as APCs. Dasatinib HeLa cells (obtained from ECACC) were seeded in chamber slides and transfected with pCI-EαGFP, pCI-EαRFP, or control plasmids pCIneo or pCI-OVAeGFP. 24 h post-transfection, B6 BMDCs prepared as described previously [14], were added and cells were co-cultured to allow DCs to acquire plasmid-expressed Ag. BMDC cultures typically contained 85–90% CD11c+ cells. 4 h later, LPS (from Salmonella equi-abortus, Sigma) was added to a final concentration

of 1 μg/ml to induce DC maturation. After 24 h co-cultured CD11c+ DCs were analysed for GFP and surface Y-Ae staining by flow cytometry and by immunofluorescence staining of cells seeded in chamber slides. Lymph node and spleen cell suspensions from TEa Tg mice were prepared as previously described [1]. The Eα peptide-specific Tg CD4 T cells were identified as CD4+Vβ6+Vα2+. B6 recipients received 0.5–1 × 106 Tg T cells in 0.2 ml intravenously in the lateral tail vein 1 day prior to immunisation. In some experiments Tg T cells were labelled with CFSE prior to adoptive transfer as previously described [15]. For EαGFP protein immunisation, different whatever doses (100 μg, 10 μg, 1 μg, 100 ng, 10 ng and 1 ng) diluted in PBS, were administered subcutaneously in the

neck scruff, each with 1 μg/dose LPS (S. equi-abortus, Sigma) as adjuvant. Control mice received PBS containing 1 μg LPS. LPS was added in order to activate APC and drive them from an antigen acquisitive to antigen presenting state as widely described in the literature. For intramuscular DNA immunisation mice received 50 μg plasmid DNA diluted in endotoxin-free PBS in a 50 μl final volume in both tibialis anterior (TA) muscles. At various times after EαGFP subcutaneous protein immunisation and subcutaneous DNA injection, cervical (CLN), brachial (BLN) and inguinal (ILN) lymph nodes were removed, macerated through Nitex mesh (Cadish and Sons, London, UK) and digested with 1 mg/ml Collagenase A (Sigma) and 10 μg/ml DNase A (Roche Diagnostics) in HBSS for 30 min at 37 °C.