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Homeostatic properties and phenotypic maturation of murine CD4+ pre-thymic emigrants in the thymus.

Dong J, Chen Y, Xu X, Jin R, Teng F, Yan F, Tang H, Li P, Sun X, Li Y, Wu H, Zhang Y, Ge Q - PLoS ONE (2013)

Bottom Line: Qa2, the expression of which indicates the phenotypic maturation of SPs and RTEs, was found to be upregulated in CD4(+) pre-RTEs in thymic perivascular space.Migratory dendritic cells that surround this region contribute to Qa2 expression in pre-RTEs.The dendritic cell-driven Qa2 induction of CD4(+) pre-RTEs is independent of MHC class II and Aire molecules.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, Peking University Health Science Center, Beijing, China.

ABSTRACT
After a tightly regulated developmental program in the thymus, "mature" single positive (SP) thymocytes leave the thymus and enter the periphery. These newly arrived recent thymic emigrants (RTEs) are phenotypically and functionally immature, and will complete a dynamic maturation in the peripheral lymphoid organs before being licensed to be resident naïve T cells. To study the early events occurring in the RTE maturation process, we identified the phenotype of CD4(+) pre-RTEs, a population of CD4(+) SP thymocytes that have acquired the thymus egress capability. Compared to peripheral naïve T cells, CD4(+) pre-RTEs displayed superior survival capability in lymphoreplete mice and faster proliferation under lymphopenic condition. The differences in Bcl2/Bim expression and/or heightened IL-7 signaling pathway may account for the pre-RTEs' better responsiveness to homeostatic signals. Qa2, the expression of which indicates the phenotypic maturation of SPs and RTEs, was found to be upregulated in CD4(+) pre-RTEs in thymic perivascular space. Migratory dendritic cells that surround this region contribute to Qa2 expression in pre-RTEs. The dendritic cell-driven Qa2 induction of CD4(+) pre-RTEs is independent of MHC class II and Aire molecules.

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Comparison of the survival of pre-RTEs (SP4 in adult animals) and naïve T cells in mice.(A) Purified SP4 thymocytes, and CD4+ naïve T cells from lymph nodes of C57BL/6 mice were labeled with CFSE and adoptively transferred into unirradiated adult C57BL/6 mice. Donor T cells from lymph nodes (LN) of the hosts were analyzed for CD44 expression and CFSE dilution (proliferation) 7 days later. The numbers in the plot display the percentage of CD44hi (upper) and CD44lo (lower) cells that diluted CFSE. (B) Unlabeled SP4 thymocytes (pre-RTEs) and CFSE-labeled CD4+ naïve T cells of CD45.1 congenic mice were mixed at 1:1 ratio and were adoptively transferred into CD45.2 C57BL/6 mice. Seven days later, the mice were sacrificed and cells were harvested from peripheral blood, lymph nodes, peyer’s patch, and spleen. Donor cells collected from host lymph nodes were shown as CD45.1+CFSE+ (naïve T) and CD45.1+CFSE- (SP4). (C) The ratio of SP4 and naïve T cells (gated as (B)) after seven days of adoptive transfer was calculated. (D) Unlabeled SP4 thymocytes and CFSE-labeled GFP+CD4+CD8- lymph node cells (RTEs) from CD45.2 mice were mixed at 1:1 ratio and were transferred into CD45.1 mice. The donor cells were gated at CD45.2+CFSE+ (RTEs) and CD45.2+CFSE- (SP4) and the ratio was analyzed 7 days later. The experiments were repeated twice and similar results were obtained. Error bars represent SEM. *P<0.05, **P<0.01, using an unpaired Student’s t test. N = 3-4 mice per group.
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pone-0056378-g002: Comparison of the survival of pre-RTEs (SP4 in adult animals) and naïve T cells in mice.(A) Purified SP4 thymocytes, and CD4+ naïve T cells from lymph nodes of C57BL/6 mice were labeled with CFSE and adoptively transferred into unirradiated adult C57BL/6 mice. Donor T cells from lymph nodes (LN) of the hosts were analyzed for CD44 expression and CFSE dilution (proliferation) 7 days later. The numbers in the plot display the percentage of CD44hi (upper) and CD44lo (lower) cells that diluted CFSE. (B) Unlabeled SP4 thymocytes (pre-RTEs) and CFSE-labeled CD4+ naïve T cells of CD45.1 congenic mice were mixed at 1:1 ratio and were adoptively transferred into CD45.2 C57BL/6 mice. Seven days later, the mice were sacrificed and cells were harvested from peripheral blood, lymph nodes, peyer’s patch, and spleen. Donor cells collected from host lymph nodes were shown as CD45.1+CFSE+ (naïve T) and CD45.1+CFSE- (SP4). (C) The ratio of SP4 and naïve T cells (gated as (B)) after seven days of adoptive transfer was calculated. (D) Unlabeled SP4 thymocytes and CFSE-labeled GFP+CD4+CD8- lymph node cells (RTEs) from CD45.2 mice were mixed at 1:1 ratio and were transferred into CD45.1 mice. The donor cells were gated at CD45.2+CFSE+ (RTEs) and CD45.2+CFSE- (SP4) and the ratio was analyzed 7 days later. The experiments were repeated twice and similar results were obtained. Error bars represent SEM. *P<0.05, **P<0.01, using an unpaired Student’s t test. N = 3-4 mice per group.

Mentions: The establishment and maintenance of a diversified T cell repertoire in the periphery requires the continual egress of pre-RTEs. Thus, the ability of pre-RTEs to respond to homeostatic signals was examined. CD4+CD44loCD62LhiCD25- naïve T cells and GFPhiCD4+ RTEs purified from lymph nodes were used as controls. As neither SP4 thymocytes nor naïve T cells proliferated in lymphoreplete mice within 7 days (Fig. 2A), we first compared the survival of these cells in mice. SP4 thymocytes and naïve T cells from CD45.1 congenic mice were mixed at 1:1 ratio and were adoptively transferred into CD45.2 congenic mice. As shown in Fig. 2C, SP4 thymocytes persist slightly but significantly better than naïve T cells in the lymph nodes and spleens of the hosts over a 7-day period (Fig. 2B-C). Similar results were obtained by adoptively transferring SP4 thymocytes and naïve T cells separately into congenic mice (data not shown). Houston, et al. showed that naïve T cells persist better than RTEs in lymphoreplete mice [30]. It implicates that there is a survival difference between pre-RTEs and RTEs. To examine this, SP4 thymocytes and RTEs purified from CD45.2 mice were co-injected into CD45.1 congenic mice. As shown in Fig. 2D, pre-RTEs and RTEs revealed very close capability in survival.


Homeostatic properties and phenotypic maturation of murine CD4+ pre-thymic emigrants in the thymus.

Dong J, Chen Y, Xu X, Jin R, Teng F, Yan F, Tang H, Li P, Sun X, Li Y, Wu H, Zhang Y, Ge Q - PLoS ONE (2013)

Comparison of the survival of pre-RTEs (SP4 in adult animals) and naïve T cells in mice.(A) Purified SP4 thymocytes, and CD4+ naïve T cells from lymph nodes of C57BL/6 mice were labeled with CFSE and adoptively transferred into unirradiated adult C57BL/6 mice. Donor T cells from lymph nodes (LN) of the hosts were analyzed for CD44 expression and CFSE dilution (proliferation) 7 days later. The numbers in the plot display the percentage of CD44hi (upper) and CD44lo (lower) cells that diluted CFSE. (B) Unlabeled SP4 thymocytes (pre-RTEs) and CFSE-labeled CD4+ naïve T cells of CD45.1 congenic mice were mixed at 1:1 ratio and were adoptively transferred into CD45.2 C57BL/6 mice. Seven days later, the mice were sacrificed and cells were harvested from peripheral blood, lymph nodes, peyer’s patch, and spleen. Donor cells collected from host lymph nodes were shown as CD45.1+CFSE+ (naïve T) and CD45.1+CFSE- (SP4). (C) The ratio of SP4 and naïve T cells (gated as (B)) after seven days of adoptive transfer was calculated. (D) Unlabeled SP4 thymocytes and CFSE-labeled GFP+CD4+CD8- lymph node cells (RTEs) from CD45.2 mice were mixed at 1:1 ratio and were transferred into CD45.1 mice. The donor cells were gated at CD45.2+CFSE+ (RTEs) and CD45.2+CFSE- (SP4) and the ratio was analyzed 7 days later. The experiments were repeated twice and similar results were obtained. Error bars represent SEM. *P<0.05, **P<0.01, using an unpaired Student’s t test. N = 3-4 mice per group.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3569422&req=5

pone-0056378-g002: Comparison of the survival of pre-RTEs (SP4 in adult animals) and naïve T cells in mice.(A) Purified SP4 thymocytes, and CD4+ naïve T cells from lymph nodes of C57BL/6 mice were labeled with CFSE and adoptively transferred into unirradiated adult C57BL/6 mice. Donor T cells from lymph nodes (LN) of the hosts were analyzed for CD44 expression and CFSE dilution (proliferation) 7 days later. The numbers in the plot display the percentage of CD44hi (upper) and CD44lo (lower) cells that diluted CFSE. (B) Unlabeled SP4 thymocytes (pre-RTEs) and CFSE-labeled CD4+ naïve T cells of CD45.1 congenic mice were mixed at 1:1 ratio and were adoptively transferred into CD45.2 C57BL/6 mice. Seven days later, the mice were sacrificed and cells were harvested from peripheral blood, lymph nodes, peyer’s patch, and spleen. Donor cells collected from host lymph nodes were shown as CD45.1+CFSE+ (naïve T) and CD45.1+CFSE- (SP4). (C) The ratio of SP4 and naïve T cells (gated as (B)) after seven days of adoptive transfer was calculated. (D) Unlabeled SP4 thymocytes and CFSE-labeled GFP+CD4+CD8- lymph node cells (RTEs) from CD45.2 mice were mixed at 1:1 ratio and were transferred into CD45.1 mice. The donor cells were gated at CD45.2+CFSE+ (RTEs) and CD45.2+CFSE- (SP4) and the ratio was analyzed 7 days later. The experiments were repeated twice and similar results were obtained. Error bars represent SEM. *P<0.05, **P<0.01, using an unpaired Student’s t test. N = 3-4 mice per group.
Mentions: The establishment and maintenance of a diversified T cell repertoire in the periphery requires the continual egress of pre-RTEs. Thus, the ability of pre-RTEs to respond to homeostatic signals was examined. CD4+CD44loCD62LhiCD25- naïve T cells and GFPhiCD4+ RTEs purified from lymph nodes were used as controls. As neither SP4 thymocytes nor naïve T cells proliferated in lymphoreplete mice within 7 days (Fig. 2A), we first compared the survival of these cells in mice. SP4 thymocytes and naïve T cells from CD45.1 congenic mice were mixed at 1:1 ratio and were adoptively transferred into CD45.2 congenic mice. As shown in Fig. 2C, SP4 thymocytes persist slightly but significantly better than naïve T cells in the lymph nodes and spleens of the hosts over a 7-day period (Fig. 2B-C). Similar results were obtained by adoptively transferring SP4 thymocytes and naïve T cells separately into congenic mice (data not shown). Houston, et al. showed that naïve T cells persist better than RTEs in lymphoreplete mice [30]. It implicates that there is a survival difference between pre-RTEs and RTEs. To examine this, SP4 thymocytes and RTEs purified from CD45.2 mice were co-injected into CD45.1 congenic mice. As shown in Fig. 2D, pre-RTEs and RTEs revealed very close capability in survival.

Bottom Line: Qa2, the expression of which indicates the phenotypic maturation of SPs and RTEs, was found to be upregulated in CD4(+) pre-RTEs in thymic perivascular space.Migratory dendritic cells that surround this region contribute to Qa2 expression in pre-RTEs.The dendritic cell-driven Qa2 induction of CD4(+) pre-RTEs is independent of MHC class II and Aire molecules.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, Peking University Health Science Center, Beijing, China.

ABSTRACT
After a tightly regulated developmental program in the thymus, "mature" single positive (SP) thymocytes leave the thymus and enter the periphery. These newly arrived recent thymic emigrants (RTEs) are phenotypically and functionally immature, and will complete a dynamic maturation in the peripheral lymphoid organs before being licensed to be resident naïve T cells. To study the early events occurring in the RTE maturation process, we identified the phenotype of CD4(+) pre-RTEs, a population of CD4(+) SP thymocytes that have acquired the thymus egress capability. Compared to peripheral naïve T cells, CD4(+) pre-RTEs displayed superior survival capability in lymphoreplete mice and faster proliferation under lymphopenic condition. The differences in Bcl2/Bim expression and/or heightened IL-7 signaling pathway may account for the pre-RTEs' better responsiveness to homeostatic signals. Qa2, the expression of which indicates the phenotypic maturation of SPs and RTEs, was found to be upregulated in CD4(+) pre-RTEs in thymic perivascular space. Migratory dendritic cells that surround this region contribute to Qa2 expression in pre-RTEs. The dendritic cell-driven Qa2 induction of CD4(+) pre-RTEs is independent of MHC class II and Aire molecules.

Show MeSH
Related in: MedlinePlus