title: Rare peripheral T cells migrate to and persist in normal mouse thymus.
abstract: The traffic of T cells between the thymus and peripheral lymphoid organs is generally thought to be unidirectional. Using a technique of lymphocyte transfer between Thy-1 congenic mice, we demonstrate here the entry of rare peripheral lymph node T cells into the normal mouse thymus. At time points from 3 h to 24 wk after transfer, donor peripheral T cells were present in the host thymus, mainly as scattered single cells confined to the medulla. At 2 wk after transfer, donor T cells constituted 0.2% of the medullary thymocytes (compared with 11% of the peripheral lymph node T cells). As a population, these cells exhibited a stable mature immunophenotype (Ly-1hi, PNAlo, and mixed L3T4- and Lyt-2+). A minority of the donor T cells expressed high levels of the MEL-14 "homing receptor". The thymic medulla thus exhibits features of a peripheral lymphoid organ but differs in its low rate of turnover of recirculating T cells.
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000950:Antigens, Ly / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D002465:Cell Movement; D013601:T-Lymphocytes / Q000145:classification / Q000502:physiology* / Q000637:transplantation; D018800:Thy-1 Antigens; D013950:Thymus Gland / Q000166:cytology* / Q000502:physiology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D018800:Thy-1 Antigens