Neural-Cadherin Influences the Homing of Terminally Differentiated Memory CD8 T Cells to the Lymph Nodes and Bone...

Memory T (T_M) cells play an important role in the long-term defense against pathogen reinvasion. However, it is still unclear how these cells receive the crucial signals necessary for their longevity and homeostatic turnover. To understand how T_M cells receive these signals, we infected mice with lymphocytic choriomeningitis virus (LCMV) and examined the expression sites of neural cadherin (N-cadherin) by immunofluorescence microscopy. We found that N-cadherin was expressed in the surroundings of the white pulps of the spleen and medulla of lymph nodes (LNs). Moreover, T_M cells expressing high levels of killer cell lectin-like receptor G1 (KLRG1), a ligand of N-cadherin, were co-localized with N-cadherin⁺ cells in the spleen but not in LNs. We then blocked N-cadherin in vivo to investigate whether it regulates the formation or function of T_M cells. The numbers of CD127^hiCD62L^hi T_M cells in the spleen of memory P14 chimeric mice declined when N-cadherin was blocked during the contraction phase, without functional impairment of these cells. In addition, when CD127^loKLRG1^hi T_M cells were adoptively transferred into anti-N-cadherin-treated mice compared with control mice, the number of these cells was reduced in the bone marrow and LNs, without functional loss. Taken together, our results suggest that N-cadherin participates in the development of CD127^hiCD62L^hi T_M cells and homing of CD127^loKLRG1^hi T_M cells to lymphoid organs.