Distinct BMI-1 and EZH2 Expression Patterns in Thymocytes and Mature T Cells Suggest a Role for Polycomb Genes in Human T Cell Differentiation

Human T cell leukemia virus type 1 (HTLV-1) is the etiologic agent of a T cell neoplasm and several inflammatory diseases. A viral gene, HTLV-1 bZIP factor (HBZ), induces pathogenic Foxp3-expressing T cells and triggers systemic inflammation and T cell lymphoma in transgenic mice, indicating its significance in HTLV-1–associated diseases. Here we show that, unexpectedly, a proinflammatory cytokine, IL-6, counteracts HBZ-mediated pathogenesis. Loss of IL-6 accelerates inflammation and lymphomagenesis in HBZ transgenic mice. IL-6 innately inhibits regulatory T cell differentiation, suggesting that IL-6 functions as a suppressor against HBZ-associated complications. HBZ up-regulates expression of the immunosuppressive cytokine IL-10. IL-10 promotes T cell proliferation only in the presence of HBZ. As a mechanism of growth promotion by IL-10, HBZ interacts with STAT1 and STAT3 and modulates the IL-10/JAK/STAT signaling pathway. These findings suggest that HTLV-1 promotes the proliferation of infected T cells by hijacking the machinery of regulatory T cell differentiation. IL-10 induced by HBZ likely suppresses the host immune response and concurrently promotes the proliferation of HTLV-1 infected T cells.

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Enhanced differentiation of functional human T cells in NSGW41 mice with tissue-specific expression of human interleukin-7

10.1101/2020.04.24.060319 ◽

2020 ◽

Author(s):

Emilie Coppin ◽

Bala Sai Sundarasetty ◽

Susann Rahmig ◽

Jonas Blume ◽

Nikita A. Verheyden ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Regulatory Elements ◽

T Cell Differentiation ◽

Human Immune System ◽

Specific Expression ◽

Hematopoietic Stem ◽

Human T Cell ◽

Human T Cells

AbstractHumanized mouse models have become increasingly valuable tools to study human hematopoiesis and infectious diseases. However, human T cell differentiation remains inefficient. We generated mice expressing human interleukin (IL-7), a critical growth and survival factor for T cells, under the control of murine IL-7 regulatory elements. After transfer of human cord blood-derived hematopoietic stem and progenitor cells, transgenic mice on the NSGW41 background, termed NSGW41hIL7, showed elevated and prolonged human cellularity in the thymus while maintaining physiological ratios of thymocyte subsets. As a consequence, numbers of functional human T cells in the periphery were increased without evidence for pathological lymphoproliferation or aberrant expansion of effector or memory-like T cells. We conclude that the novel NSGW41hIL7 strain represents an optimized mouse model for humanization to better understand human T cell differentiation in vivo and to generate a human immune system with a better approximation of human lymphocyte ratios.

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Tracking Effector T Cell Dynamics and Immune Inhibitory Receptors in Patients with Acute Myeloid Leukemia (AML)

Blood ◽

10.1182/blood.v126.23.3849.3849 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3849-3849

Author(s):

Hanna A. Knaus ◽

Raúl Montiel-Esparza ◽

Joshua F. Zeidner ◽

Amanda Blackford ◽

Christopher G. Kanakry ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Cd8 T Cells ◽

Expression Patterns ◽

T Cell Differentiation ◽

Effector Memory ◽

Inhibitory Receptors ◽

Cell Dynamics ◽

Effector T Cell

Abstract Background: Targeting specific immune inhibitory receptors (iRs) with monoclonal antibodies has led to paradigm-shifting treatment practices in a variety of solid cancers. These advances were in part driven by tremendous progress in phenotypic and functional characterization of altered iR expression patterns and memory T cell differentiation states such as exhaustion and senescence. Effector T cell dynamics and iR expression patterns in AML patients (pts) at diagnosis and after induction chemotherapy are not well understood and, if deciphered, are poised to be critically important for optimal integration of therapeutic blockade of various iRs in the clinic. Methods: We analyzed T cell dynamics and iR expression in peripheral blood (PB, n=45) and bone marrow (BM, n=38) cells from 49 pts (median age 60, range 21-76) with newly diagnosed AML. After induction, 36 (73%) pts entered complete remission (CR) whereas 13 (27%) were non responders (NR). Samples were collected at diagnosis, upon recovery after induction and following consolidation/salvage chemotherapy. Using multi-parameter flow cytometry, we characterized the differentiation status (CD45RA, CCR7), and the expression of co-stimulatory receptors (CD27, CD28) and iRs. Our gating strategy excluded NK T cells (CD3+ CD56+) from downstream analyses. Co-expression of iRs was analyzed in combination of 3 (2B4, BTLA, TIM3) or 4 (KLRG-1, CD57, PD-1 and CD160) markers. As a control, we used PB (n=41)/BM (n=16) lymphocytes from healthy controls (HC). Percentage of cells expressing specific markers were log transformed and modeled with mixed-effect linear regression models. Differential response outcomes over time were tested with interaction terms. Co-expression of multiple iRs was also analyzed with SPICE software version 5.3. Results: At diagnosis, AML pts showed significantly lower median frequency of CD8+ naïve (CD45RA+ CCR7+) T cells in PB, but higher frequencies of terminal differentiated effector memory (TEMRA; CD45RA+ CCR7-) and phenotypically senescent CD8+ CD27- CD28- CD57+ T cells. Significantly higher percentages of PB CD4+ and CD8+ T cells were found to express PD1 and 2B4 compared to HC. Additionally, the frequency of PB CD8+ T cells co-expressing 2-4 iRs was significantly higher in the PB of AML pts (Fig.1). Surprisingly, in contrast to PB, the only significant finding in the BM of AML pts at diagnosis was increased frequency of CD8+ CD27- CD28- CD57+ T cells (p<0.001) compared to HC. At the time of hematopoietic recovery from chemotherapy, TEMRAs and CD8+ CD27- CD28- CD57+ T cells significantly decreased in PB and BM of AML pts, compared to pretreatment levels. However, if analyzed by response, frequencies of these populations declined only in CR pts (p<0.001), but remained unchanged in NR pts. Analysis of iR co-expression in relation to the response to chemotherapy and time revealed that the frequency of CD8+ T cells co-expressing multiple IRs decreases in CR pts but increases in NR pts. These response-associated changes in iR co-expression were observed only in BM while, in PB, the iR co-expression profile remained unchanged irrespective of response. Finally, we assessed the effect of diverse pre-treatment factors on T cell composition at AML diagnosis. We found that older age was associated with increased frequency of CD8+ T cells expressing the iR marker KLRG-1 and the senescent T cell phenotype CD8+ CD27- CD28- CD57+ (p<0.001) but age did not affect iR co-expression on T cells in either PB or BM. CMV seropositivity was associated with increased CD8+ TEMRAs in PB and CD8+ T cells co-expressing multiple iRs (mostly Tim3 and 2B4) in both compartments. The effect of sex, cytogenetic risk group, or ELN category was insignificant. Conclusion: Our study provides critical insights into T cell differentiation and iR expression at diagnosis and during the course of treatment in pts with AML. We have identified several dominant expression patterns suggesting that iR signatures are consistent with immune recognition of AML and their role in sculpting the effector T cell responses directed against AML cell populations. However, data need to be interpreted in the context of the anatomical compartment and non-inheritable variables such as CMV and age. While ongoing work is focused on the deciphering significance of IRs expression for the interpretation of T cell functionality, our data support the rationale for therapeutic blocking of iRs in AML. Disclosures No relevant conflicts of interest to declare.

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NK-Like Homeodomain Proteins Regulate NOTCH3-Signaling in T-Cells.

Blood ◽

10.1182/blood.v112.11.1194.1194 ◽

2008 ◽

Vol 112 (11) ◽

pp. 1194-1194

Author(s):

Stefan Nagel ◽

Letizia Venturini ◽

Grzegorz K. Przybylski ◽

Piotr Grabarczyk ◽

Corinna Meyer ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Cell Lines ◽

Lymphoblastic Leukemia ◽

Expression Patterns ◽

Hematopoietic Cells ◽

Notch Pathway ◽

T Cell Differentiation ◽

Homeodomain Proteins

Abstract Three NK-like (NKL) homeobox genes, TLX1/HOX11, TLX3/HOX11L2 and NKX2- 5/CSX, have been implicated in T-cell acute lymphoblastic leukemia (T-ALL). Here we screened further NKL genes in 24 T-ALL cell lines by RT-PCR and identified common expression of MSX2, highlighting this homeobox gene as a potential physiological family member in T-cells. Subsequent quantification of MSX2 confirmed expression in primary hematopoietic cells demonstrating higher levels in CD34+ stem cells when compared to peripheral blood cells or mature CD3+ T-cells. Analysis of core thymic factors in T-ALL cell lines, including IL7, BMP4, TGFbeta, NOTCH and T-cell receptor signaling, suggests their involvement in MSX2 regulation during T-cell differentiation. Chromosomal and genomic analysis of the MSX2 locus (at 5q35) uncovered deletion in t(5;14)(q35;q32) positive T-ALL cell lines associated with low expression levels of MSX2 and ectopic activation of TLX3 or NKX2-5, respectively. For functional analysis we lentivirally transduced T-ALL cells for overexpression of either MSX2 or oncogenic TLX1 and NKX2-5. These cells displayed transcriptional activation of NOTCH3-signaling, as indicated by expression array profiling and real-time PCR analysis of NOTCH3, HES1 and HEY1. The sensitivities to gamma-secretase inhibitor analyzed by MTT-assay of cells overexpressing MSX2, TLX1 or NKX2-5, respectively, were consistently decreased. Furthermore, in addition to MSX2, both TLX1 and NKX2-5 proteins interacted with repressor proteins of the NOTCH-pathway, SPEN/MINT and TLE1/GRG1, as shown by co-immunoprecipitation, probably representing one mechanism of (de)regulation. Elevated expression of NOTCH3 and HEY1 mRNA was detected in TLX1/3 positive T-ALL patients, confirming data obtained from cell lines. In conclusion, we have defined expression patterns, regulation and targets of MSX2 in hematopoietic cells, to reveal a novel modulatory activity in T-cell differentiation operating via NOTCH-signaling, and in leukemogenesis when replaced or supplemented by oncogenic NKL homeodomain proteins.

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GATA-3 in Human T Cell Helper Type 2 Development

Journal of Experimental Medicine ◽

10.1084/jem.20031323 ◽

2004 ◽

Vol 199 (3) ◽

pp. 423-428 ◽

Cited By ~ 63

Author(s):

Alla Skapenko ◽

Jan Leipe ◽

Uwe Niesner ◽

Koen Devriendt ◽

Rolf Beetz ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Cd4 T Cells ◽

T Cell Differentiation ◽

Mrna Levels ◽

Effector Functions ◽

Th2 Cell ◽

Human T Cell

The delineation of the in vivo role of GATA-3 in human T cell differentiation is a critical step in the understanding of molecular mechanisms directing human immune responses. We examined T cell differentiation and T cell–mediated effector functions in individuals lacking one functional GATA-3 allele. CD4 T cells from GATA-3+/− individuals expressed significantly reduced levels of GATA-3, associated with markedly decreased T helper cell (Th)2 frequencies in vivo and in vitro. Moreover, Th2 cell–mediated effector functions, as assessed by serum levels of Th2-dependent immunoglobulins (Igs; IgG4, IgE), were dramatically decreased, whereas the Th1-dependent IgG1 was elevated compared with GATA-3+/+ controls. Concordant with these data, silencing of GATA-3 in GATA-3+/+ CD4 T cells with small interfering RNA significantly reduced Th2 cell differentiation. Moreover, GATA-3 mRNA levels increased under Th2-inducing conditions and decreased under Th1-inducing conditions. Taken together, the data strongly suggest that GATA-3 is an important transcription factor in regulating human Th2 cell differentiation in vivo.

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Differentiation of a CD4/CD8αβ Double Positive T Cell Population from the CD8 Pool Is Both Predictive and Sufficient to Mediate Graft-Vs-Host Disease

Blood ◽

10.1182/blood-2021-147304 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2761-2761

Author(s):

Nicholas J. Hess ◽

David Turicek ◽

Amy Hudson ◽

Peiman Hematti ◽

Jenny Gumperz ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Cell Population ◽

Cd8 T Cells ◽

Peripheral Blood ◽

Cd8 T Cell ◽

T Cell Differentiation ◽

Cell Populations ◽

Human T Cell

Abstract Acute graft-vs-host disease (aGVHD) and cancer relapse remain the primary complications following an allogeneic hematopoietic stem cell transplantation (allo-HSCT) for malignant blood disorders. While post-transplant cyclophosphamide combined with standard GVHD prophylaxis has greatly reduced the overall prevalence and severity of aGVHD, relapse rates remain a concern. There is thus a need to identify the specific human T cell populations mediating GVHD vs GVL activity as a means to develop targeted therapeutics capable of controlling aGVHD without inhibiting GVL activity. In this study, we identify a novel human T cell population that develops after transplant that is predictive and sufficient for GVHD pathology. To determine the role of human T cell populations in aGVHD, we performed xenogeneic transplantation studies using primary human graft tissue from a variety of sources (peripheral blood, G-CSF mobilized peripheral blood, bone marrow and umbilical cord blood) in addition to collecting primary human aGVHD blood samples from our clinic. Using the LD50 dose of human graft tissue, we identified a novel mature CD4 +/CD8αβ + double positive (DP) T cell population that only developed after transplantation. The development of this population was further confirmed in aGVHD patients from our clinic. The presence of DP T cells, irrespective of graft source, was also predictive of lethal GVHD in as early as one week after xenogeneic transplantation. To identify the origin of DP T cells, we transplanted isolated human CD4 or CD8 T cells into mice which showed that DP T cells only arise from the CD8 pool. Furthermore, re-transplantation of flow-sorted CD8 T cells from GVHD mice did not reveal a 2nd wave of DP T cell differentiation. This data, in addition to their highly proliferative state, suggests that DP T cells represent highly activated CD8 T cell clones. The ability of these CD8-derived DP T cells to gain CD4 expression coincides with their co-expression of both RUNX3 and THPOK, the master transcription factors of the CD8 and CD4 lineages respectively, that classically repress each other. Intracellular cytokine staining also revealed that DP T cells are the primary activated T cell population in xenogeneic GVHD, secreting both modulatory and cytotoxic cytokines (e.g. IFNγ, IL-17A, IL-22, perforin and granzyme). Ex vivo re-stimulation or re-transplantation of flow-sorted DP T cells showed that this T cell population is capable of dividing and expanding independent of CD4 and CD8 single positive T cells with the majority of the isolated DP T cells retaining their co-expression of CD4 and CD8. Finally, transplantation of either isolated human peripheral blood CD4 or CD8 T cell populations were capable of causing lethal GVHD. Conversely, re-transplantation of flow-sorted DP, CD8 or CD4 T cells from GVHD mice revealed that DP and CD4 T cells are sufficient to mediate GVHD pathology but re-transplanted CD8 T cell are not. This correlates with the absence of DP T cell differentiation in that re-transplanted CD8 population. The differentiation of DP T cells from chronically activated CD8 T cells represents a novel mechanism of GVHD pathology not previously described. The presence of DP T cells in other chronic inflammatory human diseases also suggests a broader pathology mediated by DP T cells. Further understanding of DP T cell differentiation and pathology may lead to targeted prophylaxis and/or treatment regimens for aGVHD and other human chronic inflammatory diseases. Figure 1 Figure 1. Disclosures Capitini: Nektar Therapeutics: Honoraria; Novartis: Honoraria.

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Effects of LMO2 on Human T-Cell Development Are Modulated by Notch Signaling

Blood ◽

10.1182/blood.v118.21.2470.2470 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2470-2470

Author(s):

James A Kennedy ◽

Renata Teixeira ◽

Sara Berthiaume ◽

Frederic Barabe

Keyword(s):

Gene Therapy ◽

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Notch Signaling ◽

T Cell Differentiation ◽

Human T Cell ◽

T Cell Leukemogenesis

Abstract Abstract 2470 LMO2 is overexpressed in a significant percentage of human T cell acute lymphoblastic leukemia (T-ALL) and its locus has been the target of insertional mutagenesis in gene therapy trials. In the past years, 4 X-linked severe combined immunodeficiency (X-linked SCID) and one Wiskott-Aldrich syndrome (WAS) patients who were treated by retrovirus-mediated gene therapy developed T-ALL as a result of retroviral integration in the LMO2 locus. In these patients, leukemia developed 2 to 3 years after gene therapy without prior significant haematological abnormalities. However, both the latency of disease and the finding of additional somatic mutations and/or translocations in these leukemias suggest that the overexpression of LMO2 alone is insufficient to generate leukemia, a notion that has been supported by studies in mouse. Though LMO2 is typically recognized as a T-cell oncogene, reports have shown that it is also aberrantly expressed in acute myeloid leukemias (AML), chronic myeloid leukemia (CML), B-ALL and some non-hodgkin B cell lymphomas. In order to study the impact of LMO2 overexpression on human hematopoietic stem/progenitor cells, a lentiviral vector was used to express this oncogene together with EGFP in lineage-depleted umbilical cord blood. In myeloid-promoting cultures, LMO2 had no effect on either differentiation or proliferation. Moreover, the expression of LMO2 did not modify the frequency or lineage distribution of colony forming progenitors compared to controls. However, significant differences were noted when transduced cells were assayed on OP9-Delta-Like 1 (DL1) stroma, an in vitro system that promotes T cell proliferation and differentiation. Cells overexpressing LMO2 were blocked at the double negative stage (CD4-CD8-) of differentiation and proliferated 50 to 100 times more than control cells. However, these cells were not immortalized as they proliferated for a median of 75 days, versus 50 days for controls. Immunodeficient mice transplanted with primitive human hematopoietic cells expressing LMO2 (hereafter referred as LMO2 mice) had bone marrow engraftment levels comparable to controls at 20–24 weeks post-transplant. Neither B-lymphoid nor myeloid development were affected by LMO2 overexpression. Strikingly, in the thymus, the percentage of EGFP+ cells was significantly increased in LMO2 mice compared to controls (mean of 47.7% versus 8.8%, p=0.0001), clearly indicating that expression of this oncogene enhances thymic T-cell engraftment. We next analyzed the phenotype of LMO2-expressing T cells in the thymus and peripheral blood of these mice. Surprisingly, unlike our in vitro studies, there was no evidence of a block at the DN-stage of differentiation. Instead, there were significantly less EGFP+ DN cells in the thymi of LMO2 mice compared to controls (mean of 7.5% vs 14.5%, p=0.035). These results clearly demonstrate that unlike what was observed in OP9-DL1 co-cultures, LMO2 overexpression does not induce a block in T-cell differentiation in our in vivo system. One possible explanation for this difference is the constitutive NOTCH signaling provided via DL1 on stroma compared to the in vivo setting where LMO2-expressing cells would encounter different levels and forms of NOTCH signaling throughout development. To test this hypothesis, LMO2 cells were cultured on OP9-DL1 stroma for 50 days then switched onto OP9 stroma lacking NOTCH ligand. Upon transfer, the DN cells promptly stopped proliferating and differentiated into DP (CD4+CD8+) cells expressing CD3 and TCRαβ. Thus, our results suggest that in the in vivo setting, as cells migrate through the thymus and face a decrease in NOTCH signaling, LMO2 overexpression alone can promote proliferation, but is not sufficient to maintain a differentiation block. However, constitutive NOTCH signaling can cooperate with LMO2 overexpression to block T cell differentiation at a proliferative DN stage. Thus, one can postulate that LMO2 exerts a proliferative effect on developing T-cells in thymic regions with high levels of NOTCH signaling, potentially providing a setting for the development of secondary leukemogenic events. NOTCH mutations are common in human T-ALL and can therefore allow for LMO2 overexpressing cells to become independent of the stromal niche. Taken together, our results suggest cooperation between LMO2 overexpression and NOTCH signaling in human T-cell leukemogenesis. Disclosures: No relevant conflicts of interest to declare.

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Flow cytometric assessment of human T-cell differentiation in thymus and bone marrow

Blood ◽

10.1182/blood.v79.3.666.666 ◽

1992 ◽

Vol 79 (3) ◽

pp. 666-677 ◽

Cited By ~ 152

Author(s):

LW Terstappen ◽

S Huang ◽

LJ Picker

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Cell Differentiation ◽

T Cell ◽

Cell Surface ◽

Expression Patterns ◽

Antigen Expression ◽

T Cell Differentiation ◽

Multiparameter Flow Cytometry ◽

Human T Cell

Abstract Using multidimensional flow cytometry we have defined and quantified the human T-cell differentiation pathway, focusing on those events occurring among the most immature thymocytes and putative bone marrow (BM) T-precursors. Early thymocytes were found to express the CD34 antigen and consisted of a mean 1.2% of cells within human pediatric (n = 9) and 2.0% in fetal thymi (n = 4). All CD34+ thymocytes were atypical blast by morphology, expressed intracytoplasmatic, but not cell surface, CD3, and were cell surface CD2+, CD5+, CD7+, CD38+, CD45+, CD45RA+, CD49d+, and LECAM-1(Leu8)high. CD34high thymocytes lacked surface expression of CD4 and CD8, but as CD34 expression diminished there was a coordinate increase in CD4 levels, followed by the appearance of CD8. The expression of CD1 and CD10 also increased concomitant with the loss of CD34, whereas expression of LECAM-1 diminished with CD34 downregulation. The differential expression of these antigens on early thymocytes (as well as the number of thymocytes displaying these patterns) was highly reproducible among the nine pediatric and four fetal specimens examined, suggesting a precise, stereotyped regulation of early differentiation events. Cell populations with antigen expression patterns suggestive of pluripotent stem cell (CD34high, CD38-), or non-T-lineage committed stem cells (CD34+, CD33+ or CD34+, CD19+) were not identified in either fetal or pediatric thymi (sensitivity = 1/10(4)). The presence of cells with the antigenic profile of the earliest CD34+ thymocytes was explored in human BM. Putative BM T-cell precursors with the appropriate phenotype (CD34+, CD7+, CD5+, CD2+, LECAM-1high) were readily identified in fetal specimens (constituting +/- 2% of the CD34+ population), but could not be reliably detected in adults. In contrast with thymi, only 13% of these cells expressed cytoplasmatic CD3, suggesting the presence of the immediate precursor of the putative prothymocyte population. This was further supported by the detection of CD34bright, CD7+, CD2-, CD5-, LECAM-1moderate cells in fetal specimens. Our results document the flow of cell surface differentiation during T-lymphopoiesis and suggest that T-lineage features are first acquired in the BM. The ability to reproducibly identify and isolate T-cell precursor populations of precisely defined maturational stage in marrow and thymus by multiparameter flow cytometry will facilitate characterization of the molecular events controlling T-lineage differentiation.

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Enhanced differentiation of functional human T cells in NSGW41 mice with tissue-specific expression of human interleukin-7

Leukemia ◽

10.1038/s41375-021-01259-5 ◽

2021 ◽

Author(s):

Emilie Coppin ◽

Bala Sai Sundarasetty ◽

Susann Rahmig ◽

Jonas Blume ◽

Nikita A. Verheyden ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Regulatory Elements ◽

T Cell Differentiation ◽

Human Immune System ◽

Hematopoietic Stem ◽

Interleukin 7 ◽

Human T Cell ◽

Human T Cells

AbstractHumanized mouse models have become increasingly valuable tools to study human hematopoiesis and infectious diseases. However, human T-cell differentiation remains inefficient. We generated mice expressing human interleukin-7 (IL-7), a critical growth and survival factor for T cells, under the control of murine IL-7 regulatory elements. After transfer of human cord blood-derived hematopoietic stem and progenitor cells, transgenic mice on the NSGW41 background, termed NSGW41hIL7, showed elevated and prolonged human cellularity in the thymus while maintaining physiological ratios of thymocyte subsets. As a consequence, numbers of functional human T cells in the periphery were increased without evidence for pathological lymphoproliferation or aberrant expansion of effector or memory-like T cells. We conclude that the novel NSGW41hIL7 strain represents an optimized mouse model for humanization to better understand human T-cell differentiation in vivo and to generate a human immune system with a better approximation of human lymphocyte ratios.

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Flow cytometric assessment of human T-cell differentiation in thymus and bone marrow

Blood ◽

10.1182/blood.v79.3.666.bloodjournal793666 ◽

1992 ◽

Vol 79 (3) ◽

pp. 666-677 ◽

Cited By ~ 2

Author(s):

LW Terstappen ◽

S Huang ◽

LJ Picker

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Cell Differentiation ◽

T Cell ◽

Cell Surface ◽

Expression Patterns ◽

Antigen Expression ◽

T Cell Differentiation ◽

Multiparameter Flow Cytometry ◽

Human T Cell

Using multidimensional flow cytometry we have defined and quantified the human T-cell differentiation pathway, focusing on those events occurring among the most immature thymocytes and putative bone marrow (BM) T-precursors. Early thymocytes were found to express the CD34 antigen and consisted of a mean 1.2% of cells within human pediatric (n = 9) and 2.0% in fetal thymi (n = 4). All CD34+ thymocytes were atypical blast by morphology, expressed intracytoplasmatic, but not cell surface, CD3, and were cell surface CD2+, CD5+, CD7+, CD38+, CD45+, CD45RA+, CD49d+, and LECAM-1(Leu8)high. CD34high thymocytes lacked surface expression of CD4 and CD8, but as CD34 expression diminished there was a coordinate increase in CD4 levels, followed by the appearance of CD8. The expression of CD1 and CD10 also increased concomitant with the loss of CD34, whereas expression of LECAM-1 diminished with CD34 downregulation. The differential expression of these antigens on early thymocytes (as well as the number of thymocytes displaying these patterns) was highly reproducible among the nine pediatric and four fetal specimens examined, suggesting a precise, stereotyped regulation of early differentiation events. Cell populations with antigen expression patterns suggestive of pluripotent stem cell (CD34high, CD38-), or non-T-lineage committed stem cells (CD34+, CD33+ or CD34+, CD19+) were not identified in either fetal or pediatric thymi (sensitivity = 1/10(4)). The presence of cells with the antigenic profile of the earliest CD34+ thymocytes was explored in human BM. Putative BM T-cell precursors with the appropriate phenotype (CD34+, CD7+, CD5+, CD2+, LECAM-1high) were readily identified in fetal specimens (constituting +/- 2% of the CD34+ population), but could not be reliably detected in adults. In contrast with thymi, only 13% of these cells expressed cytoplasmatic CD3, suggesting the presence of the immediate precursor of the putative prothymocyte population. This was further supported by the detection of CD34bright, CD7+, CD2-, CD5-, LECAM-1moderate cells in fetal specimens. Our results document the flow of cell surface differentiation during T-lymphopoiesis and suggest that T-lineage features are first acquired in the BM. The ability to reproducibly identify and isolate T-cell precursor populations of precisely defined maturational stage in marrow and thymus by multiparameter flow cytometry will facilitate characterization of the molecular events controlling T-lineage differentiation.

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