T cells were collected from age- and gender-matched WT, EGR1KO and EGR4KO mice. (B) WBC were collected from WT, EGR1KO and EGR4KO mice before staining and FACS analysis to determine composition (gating strategies in Appendix Fig S1). Subclasses of CD8+, CD4+ and Treg populations were determined as shown. 