Six to eight-week-old wild type C57Black/6, C57Bl/6-Tg(ACTB-EGFP)1Osb/J (Charles River laboratory) and OT II TCR transgenic (Jackson laboratory) mice were maintained in pathogen-free conditions in the animal facility of University of Murcia. All animal procedures were approved and performed according to the guidelines set by University of Murcia Institutional Animal Care and Use Committee.