Renewal and fate in the mammalian thymus: Mechanisms and inferences of thymocytokinetics

作者：B. J. Bryant · 发表于：European Journal of Immunology · 年份：1972 · DOI：10.1002/eji.1830020109 · 被引用次数：98 · 研究领域：T-cell and B-cell Immunology、Pharmacogenetics and Drug Metabolism、Single-cell and spatial transcriptomics

Abstract Quantitation of cortical thymocyte kinetics in adolescent Swiss Webster mice, using techniques of mitotic counting and [3H]TdR labeling, indicate that proliferating (P) cells and nonproliferating (Q) cells had cycle and compartment transit times of approximately 9 and 72 hours, respectively. The data also suggested that P cells may have existed in numbers greater than needed for Q cell formation, Studies of whole thymus 125I‐DNA regression after [125 I]UdR administration in mice and guinea pigs, in conjunction with the [3H]TdR data, confirmed the cortical P cell excess and indicated that it expressed a P1 to Q to P2 cytodifferentiation pathway not involving cell loss from the thymus before the end of the Q cell maturation compartmentt. Most of the matured Q cell disappeared, probably via intrathymic death. Only 2.5 to 10% of Q cells differentiated to P2 cells, according to preliminary estimation. Whole thymus P2 cell production in adolescent mice was estimated at 50 × 106 cells per day, sufficient to replace blood lymphocytes 5 times daily. However, additional estimates suggest that, if all P2 cells emigrated, less than 2.5% of them contributed to the peripheral long‐lived, thymus‐derived, lymphocyte pool. The functional and homeostatic relationships between these peripheral cells and thymic P2 cells are presently unresolved.