We next investigated whether Cd25Y129H mice exhibited signs of autoimmunity, as previously reported for mice lacking expression of various IL-2R signaling components.4,11–14 Compared with WT mice, Cd25Y129H mice showed a similar gain in body weight with age (Fig. 4a), had no substantial expansion of CD4+ or CD8+ T cells, and showed comparable percentages and absolute numbers of cells displaying a CD44hi memory phenotype (Fig. 4b). Here, CD4 is linked to Autoimmunity.