Tbx21flox flox

Six-week old female C57BL/6 mice (CD45.2, Charles River, NCI) were used for most experiments. Alternatively, six-week old female NCI B6-Ly5.1/Cr (NCI Charles River) or male B6.SJL-Ptprc Pepc/BoyJ mice (The Jackson laboratory) expressing the congenic marker CD45.1 were used as recipients for some P14 knockout adoptive transfers and CFSE tracing experiments. P14 TCR transgenic mice expressing a TCR specific for the LCMV D^bgp33-41 peptide were bred in house and backcrossed onto the C57BL/6 background. P14 Tcf7^flox/flox CD4-cre (P14TCF1KO) mice were bred in house by crossing CD4-cre mice (The Jackson laboratory) to Tcf7^flox/flox mice on the P14 background. Tbx21^flox/flox from the Jackson Laboratory (B6.128-Tbx21tm2Srnr/J) were bred in house with P14 ERT2-Cre^+/− Rosa26-YFP^+/− to generate P14 Tbx21^flox/flox ERT2-CRE^+/− Rosa-YFP^+/− mice (P14TbetKO). Tox^KO mice were kindly provided by Jonathan Kaye, PhD (Cedars-Sinai Medical Center, Los Angeles, CA, USA) and bred in house onto the P14 background to generate P14 Tox^+/− mice. All experiments and breeding conditions were in accordance with Institutional Animal Care and Use Committee (IACUC) guidelines for the University of Pennsylvania.