Rag mice

C57BL/6J (000664), CD4-Cre⁺Tg (017336), Stat6^−/−(005977), Tbx21^−/−(004648), Thy1.1 (000406), Il10Rb^−/− (005027), Il10^−/− (002250), and Prdm1^fl/fl(008100) mice were purchased from the Jackson Laboratory. Rag^−/− mice were purchased from Taconic Farms. Stat4^−/− mice were provided by M. Kaplan (Indiana University). Vav-Bcl2 Tg mice were provided by A. Nussenzweig. Stat1^−/− and Stat3^fl/fl mice were provided by D. Levy (36 (link), 37 (link)). Stat5^fl/fl mice have been described previously (38 (link)), and Prdm1-EYFP (Jax 008828) was provided by S. Crotty (La Jolla Institute for Allergy and Immunology) and E. Meffre (Yale University). All floxed mice were bred with CD4-Cre⁺ Tg mice. All animal studies were performed according to the National Institutes of Health guidelines for the use and care of live animals and were approved by the Institutional Animal Care and Use Committee of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). All in vitro experiments included two technical replicates per experiment and were performed independently two or three times, as indicated in the figure legends. All in vivo experiments were performed independently two times, with four to seven animals per group. Flow cytometry was individually performed on each animal to provide statistics.

Wild type (WT) C57BL/6 (CD45.2), WT C57BL/6 (CD45.1), and RAG^−/− mice were obtained from Taconic Farms (Germantown, NY). Eos^−/− mice were bred in house. Eos^−/− mice were generated by deleting the last three exons of the gene (Supplemental Fig. 1A). Deletion of the last coding exon from other Ikaros family paralogues has resulted in a functional null allele and mice homozygous for this Eos^−/− allele lack expression of Eos mRNA and protein. Scurfy mice were obtained from Jackson Laboratories (Bar Harbor, ME). Eos^−/− Foxp3-GFP mice were generated in house by breeding to Foxp3^EGFP mice (Jackson Stock No:006769). The Animal Care and Use Committee of the National Institute of Allergy and Infectious Diseases (NIAID) approved all experiments.

Eos^fl/fl Mice were generated and donated by C.Benoit and D. Mathis, Harvard Medical School, Boston. Eos cKO Treg mice were generated by breeding Eos^fl/fl mice with Foxp3-YFP Cre mice (Jackson Laboratory, Bar Harbor, ME). Mice with a global deletion of Eos were a generous gift of Dr. B. Morgan (Massachusetts General Hospital, Boston, MA). Mice with a deletion of Eos in all T cells were generated by breeding the Eos^fl/fl mice to CD4-Cre mice (Jackson Laboratory). Wild type (WT) C57BL/6 and RAG^−/− mice were obtained from Taconic Farms (Germantown, NY). All studies in this paper were approved by NIAID Animal Care and Use Committee. Animals of both sexes were used equally in these studies.