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标题：T cell receptor gene deletion circles identify recent thymic emigrants in the peripheral T cell pool
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作者：Fan-kun Kong ; Chen-lo H. Chen ; Adrien Six 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：4
页码：1536-1540
DOI：10.1073/pnas.96.4.1536
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Progenitor cells undergo T cell receptor (TCR) gene rearrangements during their intrathymic differentiation to become T cells. Rearrangements of the variable (V), diversity (D), and joining (J) segments of the TCR genes result in deletion of the intervening chromosomal DNA and the formation of circular episomes as a byproduct. Detection of these extrachromosomal excision circles in T cells located in the peripheral lymphoid tissues has been viewed as evidence for the existence of extrathymic T cell generation. Because all of the T cells in chickens apparently are generated in the thymus, we have employed this avian model to determine the fate of the V(D)J deletion circles. In normal animals we identified TCR V{gamma}-J{gamma} and V{beta}-D{beta} deletion circles in the blood, spleen, and intestines, as well as in the thymus. Thymectomy resulted in the gradual loss of these DNA deletion circles in all of the peripheral lymphoid tissues. A quantitative PCR analysis of V{gamma}1-J{gamma}1 and V{beta}1-D{beta} deletion circles in splenic {gamma}{delta} and V{beta}1+ {beta} T cells indicated that their numbers progressively decline after thymectomy with a half-life of approximately 2 weeks. Although TCR deletion circles therefore cannot be regarded as reliable indicators of in situ V(D)J rearrangement, measuring their levels in peripheral T cell samples can provide a valuable index of newly generated T cells entering the T cell pool.