WT and EGR4-/- CD4+ and CD8+ T cells were isolated from the spleen by cell sorting and stained with CFSE. A Cells were incubated under unstimulated conditions or stimulated with either anti-TCRβ or anti-CD3/CD28 antibodies for 0 to 5 days (mean±SEM; a minimum of 3 biological replicates were examined; each biological replicate includes 2 technical replicates). 