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Groves T, Parsons M, Miyamoto NG, Guidos CJ. TCR engagement of CD4+CD8+ thymocytes in vitro induces early aspects of positive selection, but not apoptosis. THE JOURNAL OF IMMUNOLOGY 1997. [DOI: 10.4049/jimmunol.158.1.65] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Immature CD4/CD8 double-positive (DP) thymocytes expressing self MHC-restricted TCR are positively selected in response to TCR signals to survive and differentiate into functionally competent CD4 or CD8 single positive (SP) T cells. In contrast, DP precursors expressing autoreactive TCR are clonally deleted in response to TCR signals. We show here that in vitro TCR engagement of TCR(low) DP thymocytes rapidly triggers a variety of events considered to be hallmarks of positive selection in vivo. These include increased expression of CD5 and Bcl-2, termination of RAG-1 and pre-T(alpha) gene expression, and a switch in lck promoter usage. We also demonstrate that CD4- or CD28-mediated signals synergize with TCR signals to induce these outcomes. Finally, we show that the response of DP thymocytes to TCR engagement is selective in that clonal deletion, CD4/CD8 lineage commitment, and other events associated with maturation, such as changes in expression of Thy-1, HSA, MHC class I, and CD45-RB, were not induced. Thus, only subsets of maturational processes associated with positive selection in vivo were shown to be directly coupled to TCR signaling pathways at the DP stage. These observations support conclusions from in vivo systems suggesting that multiple, temporally separated TCR engagements are required to effect the entire spectrum of developmental changes associated with positive selection, and provide a conceptual and experimental framework for unraveling the complexity of positive selection.
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52
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Groves T, Parsons M, Miyamoto NG, Guidos CJ. TCR engagement of CD4+CD8+ thymocytes in vitro induces early aspects of positive selection, but not apoptosis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1997; 158:65-75. [PMID: 8977176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Immature CD4/CD8 double-positive (DP) thymocytes expressing self MHC-restricted TCR are positively selected in response to TCR signals to survive and differentiate into functionally competent CD4 or CD8 single positive (SP) T cells. In contrast, DP precursors expressing autoreactive TCR are clonally deleted in response to TCR signals. We show here that in vitro TCR engagement of TCR(low) DP thymocytes rapidly triggers a variety of events considered to be hallmarks of positive selection in vivo. These include increased expression of CD5 and Bcl-2, termination of RAG-1 and pre-T(alpha) gene expression, and a switch in lck promoter usage. We also demonstrate that CD4- or CD28-mediated signals synergize with TCR signals to induce these outcomes. Finally, we show that the response of DP thymocytes to TCR engagement is selective in that clonal deletion, CD4/CD8 lineage commitment, and other events associated with maturation, such as changes in expression of Thy-1, HSA, MHC class I, and CD45-RB, were not induced. Thus, only subsets of maturational processes associated with positive selection in vivo were shown to be directly coupled to TCR signaling pathways at the DP stage. These observations support conclusions from in vivo systems suggesting that multiple, temporally separated TCR engagements are required to effect the entire spectrum of developmental changes associated with positive selection, and provide a conceptual and experimental framework for unraveling the complexity of positive selection.
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53
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Groves T, Smiley P, Cooke MP, Forbush K, Perlmutter RM, Guidos CJ. Fyn can partially substitute for Lck in T lymphocyte development. Immunity 1996; 5:417-28. [PMID: 8934569 DOI: 10.1016/s1074-7613(00)80498-7] [Citation(s) in RCA: 180] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lck, a Src family tyrosine kinase, transduces signals important for the development of alphabeta and gammadelta T cells. However, T cell development is only partially compromised in Lck-deficient mice, suggesting that other kinases may also transduce pre-TCR or TCR signals. One candidate is Fyn, a Src kinase coexpressed with Lck in immature and mature T cells. Here we show that T cell development is completely compromised in lck(-/-)fyn(-/-) mice. In addition, we demonstrate that expression of a gain-of-function mutant fyn(T) transgene completely restores production of immature CD4/CD8 double positive thymocytes and gammadelta T cells and improves the representation of CD4 or CD8 single positive thymocytes. These observations reveal that Fyn can subserve some Lck-like functions in T cell development.
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54
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Danska JS, Holland DP, Mariathasan S, Williams KM, Guidos CJ. Biochemical and genetic defects in the DNA-dependent protein kinase in murine scid lymphocytes. Mol Cell Biol 1996; 16:5507-17. [PMID: 8816463 PMCID: PMC231550 DOI: 10.1128/mcb.16.10.5507] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The scid gene product has been identified as the 460-kDa catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs p460), a member of the phosphatidylinositol 3-kinase family. DNA-PK activity is undetectable in scid cells, but the molecular basis for this defect has not been identified. Here we report that expression of p460 in scid lymphocyte precursors is detectable but is reduced at least 10-fold relative to that in wild-type lymphocytes. In addition, we show that the scid mutation disturbs p460 nuclear association, presumably affecting its role in DNA repair pathways. To examine the molecular basis for our observations, we used a degenerate PCR strategy to clone the C-terminal p460 kinase domain from wild-type and scid thymocytes. Northern (RNA) analysis with these probes revealed normal steady-state p460 mRNA levels in scid cells, suggesting that the reduced abundance of p460 protein is due to a posttranscriptional defect. Sequence comparisons identified a single-base-pair alteration in the scid C-terminal p460 kinase domain, resulting in a premature stop codon. This mutation is predicted to truncate p460 by approximately 8 kDa, but it preserves the conserved motifs required for kinase activity in members of the phosphoinositidyl 3-kinase family. Despite a computed molecular weight alteration of less than 2%, we were able to visualize this difference by Western blot (immunoblot) analysis of wild-type and scid p460. These data demonstrate that the scid DNA-PKes mutation is not a null allele and suggest a molecular rationale for the well-described leakiness of the scid phenotype.
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55
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Guidos CJ, Williams CJ, Grandal I, Knowles G, Huang MT, Danska JS. V(D)J recombination activates a p53-dependent DNA damage checkpoint in scid lymphocyte precursors. Genes Dev 1996; 10:2038-54. [PMID: 8769647 DOI: 10.1101/gad.10.16.2038] [Citation(s) in RCA: 224] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Double-stranded DNA breaks (DSBs) trigger p53-mediated cell cycle arrest or apoptosis pathways that limit the oncogenic consequences of exposure to genotoxic agents, but p53-mediated responses to DSB generated by normal physiologic events have not been documented. "Broken" V(D)J coding ends accumulate in scid lymphocyte precursors as a consequence of a mutation in DNA-dependent protein kinase (DNA-PK). The ensuing failure to rearrange efficiently antigen receptors arrests lymphoid development. Here we show that scid thymocytes express high levels of p53 protein, attributable to recombinase activating gene (RAG)-dependent generation of DSB adjacent to V, D, and J gene segments. To examine the functional importance of p53 expression in vivo, we bred p53-/- scid mice. The absence of p53 facilitated production of in-frame V(D)Jbeta coding joints and developmental progression of scid thymocytes, in addition to a dramatic accumulation of pro-B cells. All mice developed disseminated pro-B or immature T cell lymphoma/leukemia by 7-12 weeks of age. We present evidence that p53 deficiency prolongs the survival of scid lymphocyte precursors harboring broken V(D)J coding ends, allowing the accumulation of aneuploid cells. These results demonstrate that a p53-mediated DNA damage checkpoint contributes to the immune deficiency characteristic of the scid mutation and limits the oncogenic potential of DSBs generated during V(D)J recombination.
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MESH Headings
- Animals
- B-Lymphocytes/physiology
- Base Sequence
- Bone Marrow Cells
- Cell Cycle
- Cell Survival
- DNA Damage
- DNA Primers/chemistry
- Gamma Rays
- Gene Expression Regulation, Developmental
- Gene Rearrangement, B-Lymphocyte
- Gene Rearrangement, T-Lymphocyte
- Genes, p53
- Leukemia, Experimental/genetics
- Lymphoma/genetics
- Lymphoma/pathology
- Mice
- Mice, Mutant Strains
- Mice, SCID/genetics
- Molecular Sequence Data
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Recombination, Genetic
- T-Lymphocytes/physiology
- Thymus Gland
- Tumor Cells, Cultured/radiation effects
- Tumor Suppressor Protein p53/deficiency
- Tumor Suppressor Protein p53/physiology
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56
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Livák F, Welsh SC, Guidos CJ, Crispe IN, Danska JS, Schatz DG. Transient restoration of gene rearrangement at multiple T cell receptor loci in gamma-irradiated scid mice. J Exp Med 1996; 184:419-28. [PMID: 8760795 PMCID: PMC2192694 DOI: 10.1084/jem.184.2.419] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The developmental arrest of thymocytes from scid mice, deficient in variable, (diversity), and joining, or V(D)J recombination, can be overcome by sublethal gamma-irradiation. Since previous studies focused on restoration of rearrangement of the T cell receptor (TCR) beta locus, productive rearrangement of which is selected for, we sought to examine to what extent locus specificity and cellular selection contributed to the observed effects. We report here that irradiation of newborn scid mice induces normal V-D-J rearrangements of the TCR delta locus, which like TCR beta, is also actively rearranged in CD(4-)CD(8-) (double negative) thymocytes. In contrast, no complete V-J alpha rearrangements were detected. Instead, we detected substantial levels of hairpin-terminated coding ends at the 5' end of the J alpha locus, demonstrating that TCR alpha rearrangements manifest the effects of the scid mutation. Irradiation, therefore, transiently compensates for the effects of the scid mutation in a locus-nonspecific manner in thymocytes, resulting in a burst of normal TCR beta and delta rearrangements. Irradiation also allows the development of cells that can initiate but fail to complete V(D)J recombination events at the TCR alpha locus, which is normally inaccessible in scid thymocytes.
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MESH Headings
- Animals
- Animals, Newborn
- Base Sequence
- Female
- Gamma Rays
- Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor
- Gene Rearrangement, delta-Chain T-Cell Antigen Receptor/radiation effects
- Male
- Mice
- Mice, Inbred AKR
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, SCID/immunology
- Molecular Sequence Data
- Receptors, Antigen, T-Cell/genetics
- Recombination, Genetic
- Restriction Mapping
- Thymus Gland/cytology
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57
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Wu G, Danska JS, Guidos CJ. Lck dependence of signaling pathways activated by gamma-irradiation and CD3 epsilon engagement in RAG-1(-/-)-immature thymocytes. Int Immunol 1996; 8:1159-64. [PMID: 8757961 DOI: 10.1093/intimm/8.7.1159] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The src family tyrosine kinase, Lck, transduces signals from the pre-TCR complex which regulate the development and expansion of CD4/CD8 double-positive (DP) thymocytes from CD25(+) CD4/CD8 double-negative progenitors. We and others have recently shown that sublethal gamma-irradiation bypasses the need for TCRbeta expression to promote the development and expansion of DP thymocytes in scid or recombinase-activating gene (RAG)-deficient mice. Here we demonstrate that gamma-irradiation activates an Lck-dependent signaling process in immature thymocytes similar to that initiated physiologically by the pre-TCR complex.
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58
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Abstract
Significant progress has been made in characterizing intermediates and defining individual steps of positive selection, providing important insights into mechanisms of CD4/CD8 lineage commitment. New evidence suggests that specific recognition of peptides may be important for positive selection of CD4+ T cells. Several studies have defined signal-transduction pathways important for positive selection and have provided evidence that distinct signaling pathways may regulate positive versus negative selection.
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59
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Chen M, Tomkins DJ, Auerbach W, McKerlie C, Youssoufian H, Liu L, Gan O, Carreau M, Auerbach A, Groves T, Guidos CJ, Freedman MH, Cross J, Percy DH, Dick JE, Joyner AL, Buchwald M. Inactivation of Fac in mice produces inducible chromosomal instability and reduced fertility reminiscent of Fanconi anaemia. Nat Genet 1996; 12:448-51. [PMID: 8630504 DOI: 10.1038/ng0496-448] [Citation(s) in RCA: 198] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fanconi anaemia (FA) is an autosomal recessive disease characterized by bone marrow failure, variable congenital malformations and predisposition to malignancies. Cells derived from FA patients show elevated levels of chromosomal breakage and an increased sensitivity to bifunctional alkylating agents such as mitomycin C (MMC) and diepoxybutane (DEB). Five complementation groups have been identified by somatic cell methods, and we have cloned the gene defective in group C (FAC)(7). To understand the in vivo role of this gene, we have disrupted murine Fac and generated mice homozygous for the targeted allele. The -/- mice did not exhibit developmental abnormalities nor haematologic defects up to 9 months of age. However, their spleen cells had dramatically increased numbers of chromosomal aberrations in response to MMC and DEB. Homozygous male and female mice also had compromised gametogenesis, leading to markedly impaired fertility, a characteristic of FA patients. Thus, inactivation of Fac replicates some of the features of the human disease.
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60
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Groves T, Katis P, Madden Z, Manickam K, Ramsden D, Wu G, Guidos CJ. In vitro maturation of clonal CD4+CD8+ cell lines in response to TCR engagement. THE JOURNAL OF IMMUNOLOGY 1995. [DOI: 10.4049/jimmunol.154.10.5011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Engagement of the TCR on immature CD4+CD8+ (DP) thymocytes by an appropriate peptide/MHC ligand evokes a complex program of maturation known as positive selection. As a result, DP thymocytes are rescued from programmed cell death, become committed to the CD4 or CD8 lineage, extinguish expression of V(D)J recombinase activity, and undergo further maturation. We describe here a panel of DP thymic lymphoma cell lines that, in response to in vitro TCR engagement, undergo many of the TCR-beta-induced maturation events that have been reported to accompany positive selection of DP thymocytes in vivo. These events include increased expression of CD5, CD69, CD45, TCR-alpha, and MHC class I, and decreased expression of Thy-1 and heat-stable Ag. In addition, we observed TCR-induced expression of the bcl-2 gene, a well described inhibitor of programmed cell death. Finally, TCR engagement decreased expression of recombinase-activating genes and terminal deoxynucleotidal transferase genes, as well as V(D)J recombinase activity. However, TCR engagement did not elicit demonstrable CD4/CD8 lineage commitment. These observations suggest that engagement of the TCR on these DP cell lines elicits multiple maturation events that are part of the positive selection developmental program, but not CD4/CD8 lineage commitment. Thus, these DP cell lines provide the opportunity to elucidate molecular mechanisms of maturation and CD4/CD8 lineage commitment in vitro.
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61
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Groves T, Katis P, Madden Z, Manickam K, Ramsden D, Wu G, Guidos CJ. In vitro maturation of clonal CD4+CD8+ cell lines in response to TCR engagement. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1995; 154:5011-22. [PMID: 7730608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Engagement of the TCR on immature CD4+CD8+ (DP) thymocytes by an appropriate peptide/MHC ligand evokes a complex program of maturation known as positive selection. As a result, DP thymocytes are rescued from programmed cell death, become committed to the CD4 or CD8 lineage, extinguish expression of V(D)J recombinase activity, and undergo further maturation. We describe here a panel of DP thymic lymphoma cell lines that, in response to in vitro TCR engagement, undergo many of the TCR-beta-induced maturation events that have been reported to accompany positive selection of DP thymocytes in vivo. These events include increased expression of CD5, CD69, CD45, TCR-alpha, and MHC class I, and decreased expression of Thy-1 and heat-stable Ag. In addition, we observed TCR-induced expression of the bcl-2 gene, a well described inhibitor of programmed cell death. Finally, TCR engagement decreased expression of recombinase-activating genes and terminal deoxynucleotidal transferase genes, as well as V(D)J recombinase activity. However, TCR engagement did not elicit demonstrable CD4/CD8 lineage commitment. These observations suggest that engagement of the TCR on these DP cell lines elicits multiple maturation events that are part of the positive selection developmental program, but not CD4/CD8 lineage commitment. Thus, these DP cell lines provide the opportunity to elucidate molecular mechanisms of maturation and CD4/CD8 lineage commitment in vitro.
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62
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Guidos CJ, Williams CJ, Wu GE, Paige CJ, Danska JS. Development of CD4+CD8+ thymocytes in RAG-deficient mice through a T cell receptor beta chain-independent pathway. J Exp Med 1995; 181:1187-95. [PMID: 7869035 PMCID: PMC2191905 DOI: 10.1084/jem.181.3.1187] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Antigen-binding diversity is generated by site-specific V(D)J recombination of the T cell receptor (TCR) and immunoglobulin loci in lymphocyte precursors. Coordinate expression of two structurally distinct recombinase activating genes, RAG-1 and RAG-2, is necessary for activation of site-specific V(D)J recombination. In mice bearing targeted disruptions of either the RAG-1 or RAG-2 genes, T and B lymphocyte development is arrested at the CD4-8- double negative (DN) thymocyte or B220+/CD43+ pro-B cell stage. Development of CD4+CD8+ double positive (DP) thymocytes is restored by expression of a functionally rearranged TCR beta transgene, suggesting that TCR beta expression is critical for this developmental transition. We have found that treatment of adult or newborn RAG-deficient mice with a single sublethal dose of gamma-irradiation rescues the DN to DP transition in early thymocytes, and this is accompanied by a dramatic increase in thymus cellularity. In contrast to the observed induction of thymocyte maturation, there was no phenotypic or functional evidence of coincident B lymphocyte development in irradiated RAG-deficient mice. Interestingly, maturation of DP thymocytes occurred without expression of TCR beta protein in the cytoplasm or on the cell surface. These results suggest an in vivo pathway for DP thymocyte development which is TCR beta chain independent.
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63
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Danska JS, Pflumio F, Williams CJ, Huner O, Dick JE, Guidos CJ. Rescue of T cell-specific V(D)J recombination in SCID mice by DNA-damaging agents. Science 1994; 266:450-5. [PMID: 7524150 DOI: 10.1126/science.7524150] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Assembly of antigen receptor V (variable), D (diversity), and J (joining) gene segments requires lymphocyte-specific genes and ubiquitous DNA repair activities. Severe combined immunodeficient (SCID) mice are defective in general double-strand (ds) DNA break repair and V(D)J coding joint formation, resulting in arrested lymphocyte development. A single treatment of newborn SCID mice with DNA-damaging agents restored functional, diverse, T cell receptor beta chain coding joints, as well as development and expansion of thymocytes expressing both CD4 and CD8 coreceptors, but did not promote B cell development. Thymic lymphoma developed in all mice treated with DNA-damaging agents, suggesting an interrelation between V(D)J recombination, dsDNA break repair, and lymphomagenesis.
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64
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Feder JN, Guidos CJ, Kusler B, Carswell C, Lewis D, Schimke RT. A cell cycle analysis of growth-related genes expressed during T lymphocyte maturation. J Cell Biol 1990; 111:2693-701. [PMID: 2277081 PMCID: PMC2116351 DOI: 10.1083/jcb.111.6.2693] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Fetal liver or bone marrow-derived T lymphocyte precursors undergo extensive, developmentally regulated proliferation in response to inductive signals from the thymic microenvironment. We have used neonatal mouse thymocytes size-separated by centrifugal elutriation to study the cell cycle stage-specific expression of several genes associated with cell proliferation. These include genes involved in the biosynthesis of deoxyribonucleotide precursors, such as dihydrofolate reductase (DHFR), thymidylate synthase (TS), and the M1 and M2 subunits of ribonucleotide reductase, as well as c-myc, a cellular oncogene of unknown function. Using nuclear run-on assays, we observed that the transcription rates for these genes, with the exception of TS, are essentially invariant not only throughout the cell cycle in proliferating cells, but also in noncycling (G0) cells. The TS gene showed a transient increase in transcription rate in cells which bordered between a proliferating and nonproliferating status. Studies of an elutriated T cell line, S49.1, yielded similar results, indicating that the process of immortalization has not affected the transcriptional regulation of these genes. Analysis of steady-state mRNA levels using an RNase protection assay demonstrated that the levels of DHFR and TS mRNA accumulate as thymocytes progress through the cell cycle. In contrast, only the M2 subunit of ribonucleotide reductase showed cyclic regulation. Finally, in contrast to cultured cell models, we observed an abrupt fivefold increase in the steady-state level of c-myc mRNA in the transition from G1 to S-phase. We conclude from these studies that the transcriptional regulation of specific genes necessary for cellular proliferation is a minor component of the developmental modulation of the thymocyte cell cycle.
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65
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Guidos CJ, Danska JS, Fathman CG, Weissman IL. T cell receptor-mediated negative selection of autoreactive T lymphocyte precursors occurs after commitment to the CD4 or CD8 lineages. J Exp Med 1990; 172:835-45. [PMID: 2143774 PMCID: PMC2188558 DOI: 10.1084/jem.172.3.835] [Citation(s) in RCA: 155] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
To identify the maturational stage(s) during which T cell receptor (TCR)-mediated positive and negative selection occurs, we followed the development of CD4+8- and CD4-8+ T cells from TCRlo CD4+8+ thymic blasts in the presence of different positive and negative selecting (major histocompatibility complex or Mls) elements. We describe novel lineage-committed transitional intermediates that are TCRmed CD4+8lo or TCRmed CD4lo8+, and that show evidence of having been positively selected. Furthermore, negative selection is not evident until after cells have attained one of the TCRmed transitional phenotypes. Accordingly, we propose that negative selection in normal mice occurs only after TCRlo CD4+8+ precursors have been positively selected into either the CD4 or CD8 lineage.
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MESH Headings
- Animals
- Antigens, Differentiation, T-Lymphocyte/immunology
- Antigens, Differentiation, T-Lymphocyte/isolation & purification
- CD3 Complex
- CD4 Antigens/immunology
- CD8 Antigens
- Crosses, Genetic
- Mice
- Mice, Inbred Strains
- Models, Biological
- Oligonucleotide Probes
- Polymerase Chain Reaction
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/isolation & purification
- Species Specificity
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- Thymus Gland/immunology
- Transcription, Genetic
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66
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Guidos CJ, Weissman IL, Adkins B. Intrathymic maturation of murine T lymphocytes from CD8+ precursors. Proc Natl Acad Sci U S A 1989; 86:7542-6. [PMID: 2508090 PMCID: PMC298101 DOI: 10.1073/pnas.86.19.7542] [Citation(s) in RCA: 101] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The CD4-8- thymocyte subset contains immature precursors for phenotypically and functionally mature CD4+8- and CD4-8+ thymocytes and peripheral T cells, as well as nonmature CD4+8+ thymocytes, most of which die in situ. The intrathymic death of most thymocytes is probably related to selective influences that ensure that only those precursors bearing self-major histocompatibility complex (MHC)-restricted and self-tolerant T-cell antigen receptors (TCR) survive to complete the maturation process. Interactions between surface molecules on thymocytes (TCR, CD4, and CD8) and thymic stromal cells (MHC proteins) are critical to repertoire selection. To understand this process, the lineage relationships among immature, nonmature, and mature thymocytes must be defined. We have examined directly the precursor-progeny relationships among CD4+8-, CD4-8+, and CD4+8+ murine thymocyte subsets by assessing their short-term (less than 5 days) developmental potentials following intrathymic injection into Thy-1 congenic, unirradiated host mice. Our results identify TCR-/lo CD4-8+ and TCRlo CD4+8+ blast cells as sequential intermediates in the development of mature TCRhi CD4+8- and TCRhi CD4-8+ thymocytes from CD4-8- precursors, thus defining at least one intrathymic maturation pathway for T lymphocytes.
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67
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Guidos CJ, Weissman IL, Adkins B. Developmental potential of CD4-8- thymocytes. Peripheral progeny include mature CD4-8- T cells bearing alpha beta T cell receptor. THE JOURNAL OF IMMUNOLOGY 1989. [DOI: 10.4049/jimmunol.142.11.3773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
We have used the intra-thymic transfer system to investigate the population dynamics of thymocyte and mature T cell subsets in the absence of continuing precursor input from the bone marrow. We have followed the development and life span of CD4+ and CD8+ thymocyte subsets and mature peripheral T cells from intra-thymically injected adult or fetal CD4-8- thymic precursors. Both precursor types proliferated, differentiated, and exported to peripheral lymphoid tissues alpha beta-TCR+CD4+8- and CD4-8+ progeny which formed a stable, long-lived component of the peripheral T cell pool. The production of phenotypically mature thymocytes and peripheral T cells occurred more rapidly from fetal CD4-8- precursors. CD4+8-:CD4-8+ ratios among peripheral progeny of intra-thymically-injected CD4-8- precursors were initially normal, but they steadily declined among progeny of the fetal precursors. Thus, there appear to be differences in the life span and/or proliferative capacity of mature T cells derived from embryonic vs adult progenitors. In addition to the predominant CD4+8- and CD4-8+ subsets of peripheral T cells, a minor (1 to 20%) population of Thy-1+CD3+4-8- T cells was identified among peripheral progeny of intra-thymically-injected CD4-8- thymocytes, as well as in lymph nodes of unmanipulated animals. A total of 20 to 34% of this subset expressed V beta 8+ TCR and the majority were CD5hi, Pgp-1+, and J11d-. The function and specificity of this newly identified population of thymically derived peripheral T cells remains to be investigated.
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68
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Guidos CJ, Weissman IL, Adkins B. Developmental potential of CD4-8- thymocytes. Peripheral progeny include mature CD4-8- T cells bearing alpha beta T cell receptor. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1989; 142:3773-80. [PMID: 2785564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have used the intra-thymic transfer system to investigate the population dynamics of thymocyte and mature T cell subsets in the absence of continuing precursor input from the bone marrow. We have followed the development and life span of CD4+ and CD8+ thymocyte subsets and mature peripheral T cells from intra-thymically injected adult or fetal CD4-8- thymic precursors. Both precursor types proliferated, differentiated, and exported to peripheral lymphoid tissues alpha beta-TCR+CD4+8- and CD4-8+ progeny which formed a stable, long-lived component of the peripheral T cell pool. The production of phenotypically mature thymocytes and peripheral T cells occurred more rapidly from fetal CD4-8- precursors. CD4+8-:CD4-8+ ratios among peripheral progeny of intra-thymically-injected CD4-8- precursors were initially normal, but they steadily declined among progeny of the fetal precursors. Thus, there appear to be differences in the life span and/or proliferative capacity of mature T cells derived from embryonic vs adult progenitors. In addition to the predominant CD4+8- and CD4-8+ subsets of peripheral T cells, a minor (1 to 20%) population of Thy-1+CD3+4-8- T cells was identified among peripheral progeny of intra-thymically-injected CD4-8- thymocytes, as well as in lymph nodes of unmanipulated animals. A total of 20 to 34% of this subset expressed V beta 8+ TCR and the majority were CD5hi, Pgp-1+, and J11d-. The function and specificity of this newly identified population of thymically derived peripheral T cells remains to be investigated.
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Heimfeld S, Guidos CJ, Holzmann B, Siegelman MH, Weissman IL. Developmental analysis of the mouse hematolymphoid system. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1989; 54 Pt 1:75-85. [PMID: 2700949 DOI: 10.1101/sqb.1989.054.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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