scholarly journals Clonal Tracking of the Source of Red Cell and Platelet Production in Rhesus Macaques

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 932-932
Author(s):  
Xing Fan ◽  
Chuanfeng Wu ◽  
Diego Espinoza ◽  
Stephanie Sellers ◽  
Aylin Bonifacino ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
In Vitro Assays ◽  
Hematopoietic Stem ◽  
Post Transplant ◽  
Dna And Rna ◽  
Very High ◽  
Over Time

Abstract The classical model of hematopoietic hierarchies is being reconsidered, based on data from in vitro assays and single cell expression profiling. Recent experiments suggest that erythroid and megakaryocytic lineages might differentiate directly from multipotent hematopoietic stem/progenitor cells (HSPC) or from a highly biased subpopulations of HSPC, rather than transiting through a common MEP or CMP. We examined the clonal ontogeny of the erythroid lineage using genetic barcoding of rhesus macaque HSPC (Wu Cell Stem Cell, 2014; Koelle Blood, 2017), allowing quantitative and sensitive tracking of the in vivo clonal output of thousands of individual HSPC over time following autologous transplantation. CD34+ HSPC were lentivirally-transduced with a high diversity barcode library, with the barcode in an expressed region of the provirus, allowing barcode retrieval from DNA or RNA, with each barcode representing an individual HSPC clone. CD34+ HSPC were purified from bone marrow(BM) of 3 macaques at 3-45 months post-transplant, and plated in CFU assays. 240 colonies each of CFU-E, CFU-G and CFU-GM were plucked individually, and each colony type was pooled before DNA extraction for barcode retrieval, along with purification and barcode retrieval from concurrent BM CD34+ cells and both blood and BM T cells (T), B cells (B), granulocytes (Gr), and monocytes (Mono). The majority of barcodes retrieved from pooled CFU-E were also detected in pooled CFU-G and CFU-GM, along with purified T cells, B cells, Mono and Gr, suggesting a shared unbiased precursor pool. A small fraction of clones unique to CFU-E were identified, however, unique clones were also detected in CFU-G and in CFU-GM pools, likely reflecting low frequency clones that were to be represented randomly in the pooled CFU of each lineage. To overcome the sampling bias inherent in colony assays on any reasonable colony number, we FACS purified CD71+/CD45- nucleated maturing erythroid lineage cells (nRBC) from the BM, and compared nRBC to other lineages purified concurrently from the same BM sample. There was very high correlation of barcode contributions between BM nRBC and other BM-produced lineages, with the highest correlation between nRBC and both Gr and Mono (r> 0.9), whether at earlier or later time points. We investigated whether RNA barcode retrieval could be utilized for clonal tracking, allowing analysis of anucleate circulating RBC and thus a more global analysis of hematopoiesis compared to local BM production at a limited number of sites. We have reported that clonal output from individual HSPC remains highly geographically restricted within the BM for months-years post-transplant. We compared fractional contributions of DNA and RNA barcodes retrieved from the same sample of each lineage. There was very high correlation between DNA and RNA barcode contributions to T, B, NK, Gr and Mono lineages (r= 0.85±0.04), suggesting the differentiation pathway for these lineages does not impact significantly on expression level of barcodes from the proviral promoter, and RNA fractional contributions in these lineages reflect the clonal representation of cells in a sample. However, nRBC DNA and RNA barcode contributions were less closely related (r= 0.62), suggesting that erythroid differentiation was more likely to alter expression from loci in a manner disconnecting RNA barcode expression from clonal representation of cells in a sample, and suggesting that RNA barcode retrieval may not be ideal for comparing erythroid cells to other lineages. However, tracking RNA barcodes can be used to assess clonal stability in circulating RBC over time, and revealed very stable clonal contributions to erythropoiesis for as long as 4 years post-transplant. Finally, we used RNA barcode retrieval to compare clonal contributions between circulating platelets and other lineages. Whether DNA or RNA was used for T, B, Gr, and Mono clonal mapping, at steady state platelet RNA barcodes were clonally closely related to other lineages. But preliminary data suggests that a unique set of clones is newly recruited to contribute only to platelets following inflammatory stimuli. The presence of a separate pool of platelet-biased HSPC contributing following inflammation has been suggested by prior in vitro assays, but our model may provide the first clonal in vivo confirmation of a unique inflammation-related platelet-biased HSPC pool. Disclosures Dunbar: Novartis/GSK to institute: Research Funding.

PU.1 Is a Critical Downstream Target of AML1.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 358-358 ◽  
Author(s):  
Gang Huang ◽  
Pu Zhang ◽  
Steffen Koschmieder ◽  
Joseph D. Growney ◽  
D. Gary Gilliland ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
Fetal Liver ◽  
Proximal Region ◽  
Specific Gene ◽  
Hematopoietic Stem

Abstract PU.1 is expressed in hematopoietic stem cells (HSC), progenitors and differentiating blood cells except terminally differentiated T cells, erythrocytes and megakaryocytes. PU.1 is required for commitment of HSC to multiple lineages. PU.1 −/− embryos die perinatally and fail to generate myeloid and B cells. We previously reported that a DNase I hypersensitive site located 14 kb upstream of the PU.1 transcription start site (−14 DHS) confers myelomonocytic specific gene expression. Targeted deletion this DHS fragment in mice results in a decrease in PU.1 expression in bone marrow to 20% of wild type levels, subsequently leading to a profound decrease in macrophages and B cells. Within the DHS fragment is a “core” consisting of a distal (296bp) and a proximal (253bp) region, which are highly conserved among different species. The PU.1 promoter by itself cannot direct gene expression in vivo. However, −14 DHS confers to the promoter the ability to direct expression of a reporter gene in granulocytes, monocytes, and B-cells of transgenic mice. The proximal region can itself direct high-level gene expression. The proximal region contains 3 AML1 sites. These results, along with data indicating that PU.1 expression is selectively absent from Aml1 −/− embryos (Okada, et al, Oncogene. 1998), suggested that AML1 is likely to be upstream of PU.1. Electro-mobility gel shift assays and chromatin immunoprecipitation assays confirmed that AML1 binds to all 3 AML1 sites both in vitro and in vivo. Mutation of the 3 AML1 sites dramatically reduced the DHS activity of conferring gene expression. We used real time PCR to quantitatively measure PU.1 expression in both embryonic and adult hematopoiesis. We found that PU.1 expression was completely lost in the 9.5 dpc yolk sac, 10.5 dpc AGM and fetal liver of Aml1−/− embryos, suggesting that AML1 is required for PU.1 expression during embryonic hematopoiesis. To evaluate the effects of AML1 loss in the adult hematopoiesis, we employed a conditional Aml1 knockout allele in which LoxP flanked Aml1 (Aml1F/F) was excised by Mx1 promoter driven Cre expression following injection of pIpC. These mice show that Aml1 is not required for maturation of myeloid lineages in adult mice. However, these mice develop a mild myeloproliferative phenotype characterized by increasing in bone marrow and peripheral blood (PB) neutrophils, a 5 fold increasing in HSC, and 2–3 fold increasing myeloid progenitors. Spleen and liver contain infiltration by myeloid cells. These mice also display a dramatic decrease (~80%) in PB platelets and bone marrow megakaryocytes. Furthermore, there are significant blocks in lymphoid development, including reduced numbers of pre-B, pro-B and mature B cells, as well a block in T cell maturation at the DN2 (CD4−;CD8−;CD44+;CD25+) stage. We observed a 70% reduction of PU.1 expression in sorted HSC, progenitors, Gr1+/Mac1+ and B-cells from these mice relative to control mice. In contrast, upregulation of 3–5 fold expression in Ter119+, CD41+, and T cells in these mice compared to controls. Our data shows that PU.1 is a critical target gene of AML1, and AML1 regulates PU.1 in both positive and negative way. We are currently testing the ability of restoration of PU.1 expression to rescue specific defects in Aml1F/F; Tg (Mx1-cre) mice, as well as investigating the role of decreased PU.1 expression in human AML in which the function of AML1 is disrupted.

scholarly journals Base-edited CAR T cells for combinational therapy against T cell malignancies

Leukemia ◽  
2021 ◽  
Author(s):  
Christos Georgiadis ◽  
Jane Rasaiyaah ◽  
Soragia Athina Gkazi ◽  
Roland Preece ◽  
Aniekan Etuk ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Specific Binding ◽  
Base Editing ◽  
Car T Cells ◽  
Dna And Rna ◽  
Car T ◽  
T Cell Malignancies

AbstractTargeting T cell malignancies using chimeric antigen receptor (CAR) T cells is hindered by ‘T v T’ fratricide against shared antigens such as CD3 and CD7. Base editing offers the possibility of seamless disruption of gene expression of problematic antigens through creation of stop codons or elimination of splice sites. We describe the generation of fratricide-resistant T cells by orderly removal of TCR/CD3 and CD7 ahead of lentiviral-mediated expression of CARs specific for CD3 or CD7. Molecular interrogation of base-edited cells confirmed elimination of chromosomal translocations detected in conventional Cas9 treated cells. Interestingly, 3CAR/7CAR co-culture resulted in ‘self-enrichment’ yielding populations 99.6% TCR−/CD3−/CD7−. 3CAR or 7CAR cells were able to exert specific cytotoxicity against leukaemia lines with defined CD3 and/or CD7 expression as well as primary T-ALL cells. Co-cultured 3CAR/7CAR cells exhibited highest cytotoxicity against CD3 + CD7 + T-ALL targets in vitro and an in vivo human:murine chimeric model. While APOBEC editors can reportedly exhibit guide-independent deamination of both DNA and RNA, we found no problematic ‘off-target’ activity or promiscuous base conversion affecting CAR antigen-specific binding regions, which may otherwise redirect T cell specificity. Combinational infusion of fratricide-resistant anti-T CAR T cells may enable enhanced molecular remission ahead of allo-HSCT for T cell malignancies.

scholarly journals P01.02 TLR-mediated suppression of the CCL22-CCR4 axis as a new target for tumor immunotherapy

2021 ◽  
Vol 9 (Suppl 1) ◽  
pp. A3.2-A4
Author(s):  
J Grün ◽  
I Piseddu ◽  
C Perleberg ◽  
N Röhrle ◽  
S Endres ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
B Cells ◽  
Regulatory T Cells ◽  
Type I ◽  
List Type ◽  
Gm Csf

BackgroundUnmethylated CpG-DNA is a potent ligand for the endosomal Toll-like-receptor-9, important for the immune activation to pathogen-associated molecules.1 CpG and other TLR-ligands show effective immunotherapeutic capacities in cancer treatment by inducing an antitumorigenic immunity.2 They are able to reduce tumor progression by reduction of intratumoral secretion of the immunoregulating chemokine CCL223 and subsequent recruitment of immunosuppressive regulatory T cells (Treg), which express CCR4 the only so far known receptor for CCL22.4 Our recent work has shown that CCL22 secretion by dendritic cells (DC) in the lymph node, mediates tolerance by inducing DC-Treg contacts.5 Indeed, in the absence of CCL22, immune responses to vaccination were stronger and resulted in tumor rejection.6 Therefore, we are aiming to investigate the effects of TLR-ligands on systemic CCL22 levels, elucidating all involved mechanisms to identify new targets for cancer immunotherapy.Materials and MethodsT, B and CD11c+ DCs of wildtype (wt) and RAG1-/- mice were isolated from splenocytes by magnetic-activated cell sorting for in vitro assays. Different co-cultures were incubated with CpG and GM-CSF, known as an CCL22 inducer.5 For in vivo experiments, wt mice were treated with CpG, R484 or poly(I:C) alone and in combination with GM-CSF. CCL22-levels in a number of organs were analyzed.ResultsAnalyzing the different immune cell compartments in vitro, we found that DCs in whole splenocytes secrete CCL22 during culture while DC cultured alone showed no CCL22 secretion. When treated with CpG, CCL22-levels were reduced in splenocytes, while it was induced in DC culture alone. The same results were seen when RAG splenocytes, that lack functional B and T cells, were cultured with CpG. CpG treated B cells were able to suppress CCL22 secretion by DC unlike T cells alone. Co-cultures of T and B cells treated with CpG, however, induced the strongest CCL22 suppression in DC. In vivo, we could show that all TLR ligands tested reduced CCL22 in a number of organs significantly. Furthermore, CpG showed the strongest suppression of CCL22 even in the presence of the CCL22 inducer GM-CSF.5ConclusionsWe could show that B cells with T cells mediate CCL22 suppression by TLR ligands. The fact that CpG was able to reduce CCL22 levels even in the presence of the inducer GM-CSF demonstrates the potent CCL22 suppressive capacity of TLR ligands.ReferencesO’Neill LA, et al. The history of toll-like receptors – redefining innate immunity. Nat Rev Immunol 2013;13(6):453–60.Rothenfusser S, et al. Recent advances in immunostimulatory CpG oligonucleotides. Curr Opin Mol Ther 2003;5(2):98–106.Wang S, et al. Intratumoral injection of a CpG oligonucleotide reverts resistance to PD-1 blockade by expanding multifunctional CD8+ T cells. Proc Natl Acad Sci U S A 2016;113(46): E7240–E7249.Rapp M, et al. CCL22 controls immunity by promoting regulatory T cell communication with dendritic cells in lymph nodes. J Exp Med 2019;216(5):1170–1181.Piseddu I, et al. Constitutive expression of CCL22 is mediated by T cell-derived GM-CSF. J Immunol 2020;205(8):2056–2065.Anz D, et al. Suppression of intratumoral CCL22 by type i interferon inhibits migration of regulatory T cells and blocks cancer progression. Cancer Res 2015;75(21):4483–93.Disclosure InformationJ. Grün: None. I. Piseddu: None. C. Perleberg: None. N. Röhrle: None. S. Endres: None. D. Anz: None.

scholarly journals Impact of Different T Cell Depletion Protocols on Immune Reconstitution Following Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 43-44
Author(s):  
Amandine Pradier ◽  
Adrien Petitpas ◽  
Anne-Claire Mamez ◽  
Federica Giannotti ◽  
Sarah Morin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Reconstitution ◽  
Cell Depletion ◽  
Unrelated Donor ◽  
T Cell Depletion ◽  
Hematopoietic Stem ◽  
Post Transplant ◽  
The Impact

Introduction Allogeneic hematopoietic stem cell transplantation (HSCT) is a well-established therapeutic modality for a variety of hematological malignancies and congenital disorders. One of the major complications of the procedure is graft-versus-host-disease (GVHD) initiated by T cells co-administered with the graft. Removal of donor T cells from the graft is a widely employed and effective strategy to prevent GVHD, although its impact on post-transplant immune reconstitution might significantly affect anti-tumor and anti-infectious responses. Several approaches of T cell depletion (TCD) exist, including in vivo depletion using anti-thymocyte globulin (ATG) and/or post-transplant cyclophosphamide (PTCy) as well as in vitro manipulation of the graft. In this work, we analyzed the impact of different T cell depletion strategies on immune reconstitution after allogeneic HSCT. Methods We retrospectively analysed data from 168 patients transplanted between 2015 and 2019 at Geneva University Hospitals. In our center, several methods for TCD are being used, alone or in combination: 1) In vivo T cell depletion using ATG (ATG-Thymoglobulin 7.5 mg/kg or ATG-Fresenius 25 mg/kg); 2) in vitro partial T cell depletion (pTCD) of the graft obtained through in vitro incubation with alemtuzumab (Campath [Genzyme Corporation, Cambridge, MA]), washed before infusion and administered at day 0, followed on day +1 by an add-back of unmanipulated grafts containing about 100 × 106/kg donor T cells. The procedure is followed by donor lymphocyte infusions at incremental doses starting with 1 × 106 CD3/kg at 3 months to all patients who had received pTCD grafts with RIC in the absence of GVHD; 3) post-transplant cyclophosphamide (PTCy; 50 mg/kg) on days 3 and 4 post-HSCT. Absolute counts of CD3, CD4, CD8, CD19 and NK cells measured by flow cytometry during the first year after allogeneic HSCT were analyzed. Measures obtained from patients with mixed donor chimerism or after therapeutic DLI were excluded from the analysis. Cell numbers during time were compared using mixed-effects linear models depending on the TCD. Multivariable analysis was performed taking into account the impact of clinical factors differing between patients groups (patient's age, donor type and conditioning). Results ATG was administered to 77 (46%) patients, 15 (9%) patients received a pTCD graft and 26 (15%) patients received a combination of both ATG and pTCD graft. 24 (14%) patients were treated with PTCy and 26 (15%) patients received a T replete graft. 60% of patients had a reduced intensity conditioning (RIC). 48 (29%) patients received grafts from a sibling identical donor, 94 (56%) from a matched unrelated donor, 13 (8%) from mismatched unrelated donor and 13 (8%) received haploidentical grafts. TCD protocols had no significant impact on CD3 or CD8 T cell reconstitution during the first year post-HSCT (Figure 1). Conversely, CD4 T cells recovery was affected by the ATG/pTCD combination (coefficient ± SE: -67±28, p=0.019) when compared to the T cell replete group (Figure 1). Analysis of data censored for acute or chronic GVHD requiring treatment or relapse revealed a delay of CD4 T cell reconstitution in the ATG and/or pTCD treated groups on (ATG:-79±27, p=0.004; pTCD:-100±43, p=0.022; ATG/pTCD:-110±33, p<0.001). Interestingly, pTCD alone or in combination with ATG resulted in a better reconstitution of NK cells compared to T replete group (pTCD: 152±45, p<0.001; ATG/pTCD: 94±36, p=0.009; Figure 1). A similar effect of pTCD was also observed for B cells (pTCD: 170±48, p<.001; ATG/pTCD: 127±38, p<.001). The effect of pTCD on NK was confirmed when data were censored for GVHD and relapse (pTCD: 132±60, p=0.028; ATG/pTCD: 106±47, p=0.023) while only ATG/pTCD retained a significant impact on B cells (102±49, p=0.037). The use of PTCy did not affect T, NK or B cell reconstitution when compared to the T cell replete group. Conclusion Our results indicate that all TCD protocols with the only exception of PTCy are associated with a delayed recovery of CD4 T cells whereas pTCD of the graft, alone or in combination with ATG, significantly improves NK and B cell reconstitution. Figure 1 Disclosures No relevant conflicts of interest to declare.

scholarly journals IMMUNOLOGIC REACTIONS TO HAPTENS ON AUTOLOGOUS CARRIERS

1973 ◽  
Vol 137 (2) ◽  
pp. 411-423 ◽  
Author(s):  
John W. Moorhead ◽  
Curla S. Walters ◽  
Henry N. Claman
Keyword(s):  
T Cells ◽  
B Cells ◽  
Aminocaproic Acid ◽  
Single Amino Acid ◽  
Secondary Response ◽  
Spleen Cells ◽  
Activated T Cells ◽  
Thymus Cells

Both thymus-derived (T) and bone marrow-derived (B) lymphocytes participate in the response to a hapten 4-hydroxy-3-iodo-5-nitrophenylacetic acid (NIP), coupled to a nonimmunogenic isologous carrier, mouse gamma globulin (MGG). Spleen cells from mice immunized with NIP-MGG show increased DNA synthesis in vitro when cultured with NIP-MGG. The participation of and requirement for T cells in the response was demonstrated by treating the spleen cells with anti-θ serum. This treatment resulted in a 77% inhibition of the antigen response. Furthermore, adoptively transferred normal thymus cells could be specifically "activated" by NIP-MGG in vivo and they responded secondarily to the antigen in vitro. The active participation of B cells in the secondary response was demonstrated by passing the immune spleen cells through a column coated with polyvalent anti-MGG serum. Column filtration reduced the number of NIP-specific plaque-forming cells and NIP-specific rosette-forming cells (both functions of B cells) and produced a 47% inhibition of the NIP-MGG response. The ability of the cells to respond to phytohemagglutinin (PHA) was not affected by column filtration showing that T cells were not being selectively removed. The participation of B cells in the in vitro NIP-MGG response was also shown by treatment of the spleen cells with antiserum specific for MGG and MGG determinants. B cells were removed by treatment with anti-IgM or polyvalent anti-MGG serum plus complement, resulting in a respective 46 and 49% inhibition of the response to NIP-MGG. (Treatment with anti-IgM serum had no effect on T cells.) The contribution of the hapten NIP to stimulation of T cells was investigated using NIP-MGG-activated thymus cells. These activated T cells responded in vitro very well to the NIP-MGG complex but not to the MGG carrier alone demonstrating the requirement of the hapten for T cell stimulation. The response was also partially inhibited (41%) by incubating the activated cells with NIP coupled to a single amino acid (epsilon-aminocaproic acid) before addition of NIP-MGG. These results demonstrated that T cells recognize the hapten NIP when it is coupled to the isologous carrier MGG.

scholarly journals High levels of interleukin 10 production in vivo are associated with tolerance in SCID patients transplanted with HLA mismatched hematopoietic stem cells.

1994 ◽  
Vol 179 (2) ◽  
pp. 493-502 ◽  
Author(s):  
R Bacchetta ◽  
M Bigler ◽  
J L Touraine ◽  
R Parkman ◽  
P A Tovo ◽  
...  
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
T Cell ◽  
Mrna Expression ◽  
Fetal Liver ◽  
Hla Antigens ◽  
Interleukin 10 ◽  
Hematopoietic Stem

Transplantation of HLA mismatched hematopoietic stem cells in patients with severe combined immunodeficiency (SCID) can result in a selective engraftment of T cells of donor origin with complete immunologic reconstitution and in vivo tolerance. The latter may occur in the absence of clonal deletion of donor T lymphocytes able to recognize the host HLA antigens. The activity of these host-reactive T cells is suppressed in vivo, since no graft-vs. -host disease is observed in these human chimeras. Here it is shown that the CD4+ host-reactive T cell clones isolated from a SCID patient transplanted with fetal liver stem cells produce unusually high quantities of interleukin 10 (IL-10) and very low amounts of IL-2 after antigen-specific stimulation in vitro. The specific proliferative responses of the host-reactive T cell clones were considerably enhanced in the presence of neutralizing concentrations of an anti-IL-10 monoclonal antibody, suggesting that high levels of endogenous IL-10 suppress the activity of these cells. These in vitro data correlate with observations made in vivo. Semi-quantitative polymerase chain reaction analysis carried out on freshly isolated peripheral blood mononuclear cells (PBMC) of the patient indicated that the levels of IL-10 messenger RNA (mRNA) expression were strongly enhanced, whereas IL-2 mRNA expression was much lower than that in PBMC of healthy donors. In vivo IL-10 mRNA expression was not only high in the T cells, but also in the non-T cell fraction, indicating that host cells also contributed to the high levels of IL-10 in vivo. Patient-derived monocytes were found to be major IL-10 producers. Although no circulating IL-10 could be detected, freshly isolated monocytes of the patient showed a reduced expression of class II HLA antigens. However, their capacity to stimulate T cells of normal donors in primary mixed lymphocyte cultures was within the normal range. Interestingly, similar high in vivo IL-10 mRNA expressions in the T and non-T cell compartment were also observed in three SCID patients transplanted with fetal liver stem cells and in four SCID patients transplanted with T cell-depleted haploidentical bone marrow stem cells. Taken together, these data indicate that high endogenous IL-10 production is a general phenomenon in SCID patients in whom allogenic stem cell transplantation results in immunologic reconstitution and induction of tolerance. Both donor T cells and host accessory cells contribute to these high levels of IL-10, which would suppress the activity of host-reactive T cell in vivo.

scholarly journals Transcription factor Etv6 regulates functional differentiation of cross-presenting classical dendritic cells

2018 ◽  
Vol 215 (9) ◽  
pp. 2265-2278 ◽  
Author(s):  
Colleen M. Lau ◽  
Ioanna Tiniakou ◽  
Oriana A. Perez ◽  
Margaret E. Kirkling ◽  
George S. Yap ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Transcription Factor ◽  
T Cell ◽  
Cd8 T Cells ◽  
Functional Differentiation ◽  
Specific Gene ◽  
Hematopoietic Stem

An IRF8-dependent subset of conventional dendritic cells (cDCs), termed cDC1, effectively cross-primes CD8+ T cells and facilitates tumor-specific T cell responses. Etv6 is an ETS family transcription factor that controls hematopoietic stem and progenitor cell (HSPC) function and thrombopoiesis. We report that like HSPCs, cDCs express Etv6, but not its antagonist, ETS1, whereas interferon-producing plasmacytoid dendritic cells (pDCs) express both factors. Deletion of Etv6 in the bone marrow impaired the generation of cDC1-like cells in vitro and abolished the expression of signature marker CD8α on cDC1 in vivo. Moreover, Etv6-deficient primary cDC1 showed a partial reduction of cDC-specific and cDC1-specific gene expression and chromatin signatures and an aberrant up-regulation of pDC-specific signatures. Accordingly, DC-specific Etv6 deletion impaired CD8+ T cell cross-priming and the generation of tumor antigen–specific CD8+ T cells. Thus, Etv6 optimizes the resolution of cDC1 and pDC expression programs and the functional fitness of cDC1, thereby facilitating T cell cross-priming and tumor-specific responses.

scholarly journals Hematopoietic lineage-converted T cells carrying tumor-associated antigen-recognizing TCRs effectively kill tumor cells

2020 ◽  
Vol 8 (2) ◽  
pp. e000498
Author(s):  
Fangxiao Hu ◽  
Dehao Huang ◽  
Yuxuan Luo ◽  
Peiqing Zhou ◽  
Cui Lv ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Tumor Cells ◽  
Cell Receptor ◽  
Histocompatibility Complex ◽  
Tumor Associated Antigen ◽  
Engineered T Cells ◽  
Antitumor Immunotherapy

Tumor-associated antigen (TAA) T-cell receptor (TCR) gene-engineered T cells exhibit great potential in antitumor immunotherapy. Considering the high costs and low availability of patient-derived peripheral blood T cells, substantial efforts have been made to explore alternatives to natural T cells. We previously reported that enforced expression of Hoxb5 converted B cells into induced T (iT) cells in vivo. Here, we successfully regenerated naive OT1 (major histocompatibility complex I restricted ovalbumin antigen) iT cells (OT1-iT) in vivo by expressing Hoxb5 in pro-pre-B cells in the OT1 transgenic mouse. The OT1-iT cells can be activated and expanded in vitro in the presence of tumor cells. Particularly, these regenerated OT1-iT cells effectively eradicated tumor cells expressing the TAA (ovalbumin) both in vitro and in vivo. This study provides insights into the translational applications of blood lineage-transdifferentiated T cells in immunotherapy.

scholarly journals Genetic control of immune response to myoglobin. Ir gene function in genetic restriction between T and B lymphocytes.

1982 ◽  
Vol 156 (5) ◽  
pp. 1486-1501 ◽  
Author(s):  
Y Kohno ◽  
J A Berzofsky
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
High Responder ◽  
Gene Control ◽  
Gene Defect ◽  
Genetic Restriction ◽  
Low Responder

We studied the genetic restrictions on the interaction between T cells, B cells, and antigen-presenting cells (APC) involved in the H-2-linked Ir gene control of the in vitro secondary antibody response to sperm whale myoglobin (Mb) in mice. The B cells in this study were specific for Mb itself, rather than for a hapten unrelated to the Ir gene control, as in many previous studies. Low responder mice immunized in vivo with Mb bound to an immunogenic carrier, fowl gamma globulin (F gamma G), produced B cells competent to secrete anti-Mb antibodies in vitro if they received F gamma G-specific T cell help. However, (high-responder X low responder) F1 T cells from Mb-immune mice did not help these primed low responder (H-2k or H-2b) B cells in vitro, even in the presence of various numbers of F1 APC that were demonstrated to be component to reconstitute the response of spleen cells depleted by APC. Similar results were obtained with B6 leads to B6D2F1 radiation bone marrow chimeras. Genotypic low responder (H-2b) T cells from these mice helped Mb-primed B6D2F1B cells plus APC, but did not help syngeneic chimeric H-2b B cells, even in the presence of F1 APC. In contrast, we could not detect any Ir restriction on APC function during these in vitro secondary responses. Moreover, in the preceding paper, we found that low responder mice neonatally tolerized to higher responder H-2 had competent Mb-specific helper T cells capable of helping high responder but not low responder B cells and APC. Therefore, although function Mb-specific T cells and B cells both exist in low responder mice, the Ir gene defect is a manifestation of the failure of syngeneic collaboration between these two cell types. This genetic restriction on the interaction between T cells and B cells is consistent with the additional new finding that Lyb-5-negative B cells are a major participant in ths vitro secondary response because it is this Lyb-5-negative subpopulation of B cells that have recently been shown to require genetically restricted help. The Ir gene defect behaves operationally as a failure of low responder B cells to receive help from any source of Mb-specific T cells either high responder, low responder, or F1. The possible additional role of T cell-APC interactions, either during primary immunization in vivo or in the secondary culture is discussed.

scholarly journals The Pu.1 Locus Is Differentially Regulated at the Level of Chromatin Structure and Noncoding Transcription by Alternate Mechanisms at Distinct Developmental Stages of Hematopoiesis

2007 ◽  
Vol 27 (21) ◽  
pp. 7425-7438 ◽  
Author(s):  
Maarten Hoogenkamp ◽  
Hanna Krysinska ◽  
Richard Ingram ◽  
Gang Huang ◽  
Rachael Barlow ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
Transcription Factors ◽  
B Cells ◽  
Regulatory Element ◽  
Precursor Cells ◽  
Hematopoietic Stem ◽  
Tissue Specific ◽  
Specific Regulation

ABSTRACT The Ets family transcription factor PU.1 is crucial for the regulation of hematopoietic development. Pu.1 is activated in hematopoietic stem cells and is expressed in mast cells, B cells, granulocytes, and macrophages but is switched off in T cells. Many of the transcription factors regulating Pu.1 have been identified, but little is known about how they organize Pu.1 chromatin in development. We analyzed the Pu.1 promoter and the upstream regulatory element (URE) using in vivo footprinting and chromatin immunoprecipitation assays. In B cells, Pu.1 was bound by a set of transcription factors different from that in myeloid cells and adopted alternative chromatin architectures. In T cells, Pu.1 chromatin at the URE was open and the same transcription factor binding sites were occupied as in B cells. The transcription factor RUNX1 was bound to the URE in precursor cells, but binding was down-regulated in maturing cells. In PU.1 knockout precursor cells, the Ets factor Fli-1 compensated for the lack of PU.1, and both proteins could occupy a subset of Pu.1 cis elements in PU.1-expressing cells. In addition, we identified novel URE-derived noncoding transcripts subject to tissue-specific regulation. Our results provide important insights into how overlapping, but different, sets of transcription factors program tissue-specific chromatin structures in the hematopoietic system.

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