Characterization of CD44low CD62Llow CD8 T-cell subset

To characterize CD44low CD62low CD8 T-cell subset (P4), we compared gene expression among four CD8 T-cell subsets. A hierarchical clustering of global gene expression showed that each subset of CD8 T-cells expresses a distinct gene profile. Genes expressed in activated T-cells were highly expressed in P4 cells compared to naive P1 cells. On the other hand, genes expressed in differentiated T-cells were less expressed in P4 cells compared to either central memory (P2) or effector/memory (P3) cells. These results indicate that P4 cells are in an activated, but pre-mature state and distinct from more differentiated subsets of CD8 T-cells such as central memory and effector/memory cells. FACS sorted CD8 subset cells from spleens and lymph nodes of PD-1-/- C57BL/6 mice