Increased generation of CD8 single positive cells in SOCS1-deficient thymus does not proportionately increase their export

详细信息    查看全文

• 作者：Subburaj Ilangumaran ; Julien Gagnon ; Chantal Leblanc ; Philippe Poussier ; Sheela Ramanathan
• 关键词：T lymphocyte ; Homeostasis ; SOCS1 ; Thymic export
• 刊名：Immunology Letters
• 出版年：2010
• 出版时间：16 August 2010
• 年：2010
• 卷：132
• 期：1-2
• 页码：12-17
• 全文大小：422 K

文摘

Mice lacking suppressor of cytokine signaling 1 (SOCS1) accumulate CD8⁺ T lymphocytes in the thymus and in the periphery. Whereas IL-7 and IL-15 promote the generation of CD8 single positive (SP) thymocytes, IL-15 drives the expansion of CD8 T cells in the periphery. Here, we investigated whether increased production of CD8 SP thymocytes is accompanied by their increased export in SOCS1-deficient mice. In vivo labeling with bromodeoxyuridine showed increased cycling of CD8 SP thymocytes in SOCS1-deficient mice. However, SOCS1-deficient thymi contained increased proportion of CD24^loCD69^lo SP thymocytes as well as increased expression of Qa-2 in both CD4 and CD8 SP compartments. Analysis of recent thymic emigrants (RTE) following intrathymic labeling with fluorescein isothiocyanate revealed less efficient export of CD8 RTEs from SOCS1-deficient thymi and comparable CD4:CD8 ratio among RTEs in SOCS1-null and control mice. These findings show that the rate of export of CD8 SP thymocytes is not proportional to their generation in SOCS1-deficient thymi and suggest the existence of homeostatic mechanisms controlling the egress of CD8 T cells.