CD8A and cyclic hematopoiesis: To investigate whether the Ly6C+CD8+ Tn cells in mice cells exhibit enhanced functional response, we sorted Ly6C ± CD3+CD8+CD62L+CD44lo cells from secondary lymphoid tissues of SPF and CH mice (Fig. 3A, complete gating strategy in Fig. S7A) and stimulated them with α-CD3/α-CD28 beads and phorbol-myristate acetate (PMA) and the calcium ionophore ionomycin.