For in vitro T cell stimulation assays, PMA (Sigma-Aldrich) was used at 50 ng/ml and ionomycin (Sigma-Aldrich) was used at 1 μg/ml final concentrations. For CsA (Calbiochem) treatment, 10x stock solutions were prepared in EtOH. CsA stocks were diluted with olive oil (Sigma-Aldrich) and, after thorough mixing, were injected i.p. at a dose of 80 mg/kg. For tacrolimus (Calbiochem), the final treatment dose was 2.5 mg/kg.