scholarly journals Defining APOBEC3 Expression Patterns in Human Tissues and Hematopoietic Cell Subsets

2009 ◽  
Vol 83 (18) ◽  
pp. 9474-9485 ◽  
Author(s):  
Fransje A. Koning ◽  
Edmund N. C. Newman ◽  
Eun-Young Kim ◽  
Kevin J. Kunstman ◽  
Steven M. Wolinsky ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Expression Patterns ◽  
Hematopoietic Cell ◽  
Mrna Levels ◽  
Cell Content ◽  
Hiv 1

ABSTRACT Human APOBEC3 enzymes are cellular DNA cytidine deaminases that inhibit and/or mutate a variety of retroviruses, retrotransposons, and DNA viruses. Here, we report a detailed examination of human APOBEC3 gene expression, focusing on APOBEC3G (A3G) and APOBEC3F (A3F), which are potent inhibitors of human immunodeficiency virus type 1 (HIV-1) infection but are suppressed by HIV-1 Vif. A3G and A3F are expressed widely in hematopoietic cell populations, including T cells, B cells, and myeloid cells, as well as in tissues where mRNA levels broadly correlate with the lymphoid cell content (gonadal tissues are exceptions). By measuring mRNA copy numbers, we find that A3G mRNA is ∼10-fold more abundant than A3F mRNA, implying that A3G is the more significant anti-HIV-1 factor in vivo. A3G and A3F levels also vary between donors, and these differences are sustained over 12 months. Responses to T-cell activation or cytokines reveal that A3G and A3F mRNA levels are induced ∼10-fold in macrophages and dendritic cells (DCs) by alpha interferon (IFN-α) and ∼4-fold in naïve CD4+ T cells. However, immunoblotting revealed that A3G protein levels are induced by IFN-α in macrophages and DCs but not in T cells. In contrast, T-cell activation and IFN-γ had a minimal impact on A3G or A3F expression. Finally, we noted that A3A mRNA expression and protein expression are exquisitely sensitive to IFN-α induction in CD4+ T cells, macrophages, and DCs but not to T-cell activation or other cytokines. Given that A3A does not affect HIV-1 infection, these observations imply that this protein may participate in early antiviral innate immune responses.

scholarly journals Activation of virus replication after vaccination of HIV-1-infected individuals.

1995 ◽  
Vol 182 (6) ◽  
pp. 1727-1737 ◽  
Author(s):  
S I Staprans ◽  
B L Hamilton ◽  
S E Follansbee ◽  
T Elbeik ◽  
P Barbosa ◽  
...  
Keyword(s):  
T Cells ◽  
Steady State ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Vaccine Antigens ◽  
Steady State Levels ◽  
Hiv 1

Little is known about the factors that govern the level of HIV-1 replication in infected individuals. Recent studies (using potent antiviral drugs) of the kinetics of HIV-1 replication in vivo have demonstrated that steady-state levels of viremia are sustained by continuous rounds of de novo infection and the associated rapid turnover of CD4+ T lymphocytes. However, no information is available concerning the biologic variables that determine the size of the pool of T cells that are susceptible to virus infection or the amount of virus produced from infected cells. Furthermore, it is not known whether all CD4+ T lymphocytes are equally susceptible to HIV-1 infection at a given time or whether the infection is focused on cells of a particular state of activation or antigenic specificity. Although HIV-1 replication in culture is known to be greatly facilitated by T cell activation, the ability of specific antigenic stimulation to augment HIV-1 replication in vivo has not been studied. We sought to determine whether vaccination of HIV-1-infected adults leads to activation of virus replication and the targeting of vaccine antigen-responsive T cells for virus infection and destruction. Should T cell activation resulting from exposure to environmental antigens prove to be an important determinant of the steady-state levels of HIV-1 replication in vivo and lead to the preferential loss of specific populations of CD4+ T lymphocytes, it would have significant implications for our understanding of and therapeutic strategies for HIV-1 disease. To begin to address these issues, HIV-1-infected individuals and uninfected controls were studied by measurement of immune responses to influenza antigens and quantitation of virion-associated plasma HIV-1 RNA levels at baseline and at intervals after immunization with the trivalent influenza vaccine. Influenza vaccination resulted in readily demonstrable but transient increases in plasma HIV-1 RNA levels, indicative of activation of viral replication, in HIV-1-infected individuals with preserved ability to immunologically respond to vaccine antigens. Activation of HIV-1 replication by vaccination was more often seen and of greater magnitude in individuals who displayed a T cell proliferative response to vaccine antigens at baseline and in those who mounted a significant serologic response after vaccination. The fold increase in viremia, as well as the rates of increase of HIV-1 in plasma after vaccination and rates of viral decline after peak viremia, were higher in individuals with higher CD4+ T cell counts.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Chronic CD4+ T-Cell Activation and Depletion in Human Immunodeficiency Virus Type 1 Infection: Type I Interferon-Mediated Disruption of T-Cell Dynamics

2007 ◽  
Vol 82 (4) ◽  
pp. 1870-1883 ◽  
Author(s):  
Ahmad R. Sedaghat ◽  
Jennifer German ◽  
Tanya M. Teslovich ◽  
Joseph Cofrancesco ◽  
Chunfa C. Jie ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Type I Interferon ◽  
Type I ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The mechanism of CD4+ T-cell depletion during chronic human immunodeficiency virus type 1 (HIV-1) infection remains unknown. Many studies suggest a significant role for chronic CD4+ T-cell activation. We assumed that the pathogenic process of excessive CD4+ T-cell activation would be reflected in the transcriptional profiles of activated CD4+ T cells. Here we demonstrate that the transcriptional programs of in vivo-activated CD4+ T cells from untreated HIV-positive (HIV+) individuals are clearly different from those of activated CD4+ T cells from HIV-negative (HIV−) individuals. We observed a dramatic up-regulation of cell cycle-associated and interferon-stimulated transcripts in activated CD4+ T cells of untreated HIV+ individuals. Furthermore, we find an enrichment of proliferative and type I interferon-responsive transcription factor binding sites in the promoters of genes that are differentially expressed in activated CD4+ T cells of untreated HIV+ individuals compared to those of HIV− individuals. We confirm these findings by examination of in vivo-activated CD4+ T cells. Taken together, these results suggest that activated CD4+ T cells from untreated HIV+ individuals are in a hyperproliferative state that is modulated by type I interferons. From these results, we propose a new model for CD4+ T-cell depletion during chronic HIV-1 infection.

scholarly journals Human Endothelial Cells Enhance Human Immunodeficiency Virus Type 1 Replication in CD4+ T Cells in a Nef-Dependent Manner In Vitro and In Vivo

2005 ◽  
Vol 79 (1) ◽  
pp. 264-276 ◽  
Author(s):  
Jaehyuk Choi ◽  
Jason Walker ◽  
Sergei Boichuk ◽  
Nancy Kirkiles-Smith ◽  
Nicholas Torpey ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Dependent Manner ◽  
Wild Type ◽  
Mhc Ii ◽  
Hiv 1

ABSTRACT Infected CD4+ T cells are the primary sites of human immunodeficiency virus type 1 (HIV-1) replication in vivo. However, signals from professional antigen-presenting cells (APCs), such as dendritic cells and macrophages, greatly enhance HIV-1 replication in T cells. Here, we report that in cocultures, vascular endothelial cells (ECs), which in humans can also serve as APCs, can enhance HIV-1 production of both CCR5- and CXCR4-utilizing strains approximately 50,000-fold. The observed HIV-1 replication enhancement conferred by ECs occurred only in memory CD4+ T cells, required expression of major histocompatibility complex class II (MHC-II) molecules by the ECs, and could not be conferred by fixed ECs, all of which are consistent with a requirement for EC-mediated T-cell activation via T-cell receptor (TCR) signaling. Deletion of nef (Nef−) decreased HIV-1 production by approximately 100-fold in T cells cocultured with ECs but had no effect on virus production in T cells cocultured with professional APCs or fibroblasts induced to express MHC-II. Human ECs do not express B7 costimulators, but Nef− replication in CD4+-T-cell and EC cocultures could not be rescued by anti-CD28 antibody. ECs act in trans to enhance wild-type but not Nef− replication and facilitate enhanced wild-type replication in naïve T cells when added to T-cell or B-lymphoblastoid cell cocultures, suggesting that ECs also provide a TCR-independent signal to infected T cells. Consistent with these in vitro observations, wild-type HIV-1 replicated 30- to 50-fold more than Nef− in human T cells infiltrating allogeneic human skin grafts on human huPBL-SCID/bg mice, an in vivo model of T-cell activation by ECs. Our studies suggest that ECs, which line the entire cardiovascular system and are, per force, in frequent contact with memory CD4+ T cells, provide signals to HIV-1-infected CD4+ T cells to greatly enhance HIV-1 production in a Nef-dependent manner, a mechanism that could contribute to the development of AIDS.

scholarly journals Bifunctional iRGD-anti-CD3 enhances antitumor potency of T cells by facilitating tumor infiltration and T-cell activation

2021 ◽  
Vol 9 (5) ◽  
pp. e001925
Author(s):  
Shujuan Zhou ◽  
Fanyan Meng ◽  
Shiyao Du ◽  
Hanqing Qian ◽  
Naiqing Ding ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Confocal Microscope ◽  
Mechanistic Studies ◽  
Tumor Spheroids ◽  
Antitumor Effects ◽  
Transport Pathway

BackgroundPoor infiltration and limited activation of transferred T cells are fundamental factors impeding the development of adoptive cell immunotherapy in solid tumors. A tumor-penetrating peptide iRGD has been widely used to deliver drugs deep into tumor tissues. CD3-targeting bispecific antibodies represent a promising immunotherapy which recruits and activates T cells.MethodsT-cell penetration was demonstrated in tumor spheroids using confocal microscope, and in xenografted tumors by histology and in vivo real-time fluorescence imaging. Activation and cytotoxicity of T cells were assessed by flow cytometry and confocal microscope. Bioluminescence imaging was used to evaluate in vivo antitumor effects, and transmission electron microscopy was used for mechanistic studies.ResultsWe generated a novel bifunctional agent iRGD-anti-CD3 which could immobilize iRGD on the surface of T cells through CD3 engaging. We found that iRGD-anti-CD3 modification not only facilitated T-cell infiltration in 3D tumor spheroids and xenografted tumor nodules but also induced T-cell activation and cytotoxicity against target cancer cells. T cells modified with iRGD-anti-CD3 significantly inhibited tumor growth and prolonged survival in several xenograft mouse models, which was further enhanced by the combination of programmed cell death protein 1 (PD-1) blockade. Mechanistic studies revealed that iRGD-anti-CD3 initiated a transport pathway called vesiculovacuolar organelles in the endothelial cytoplasm to promote T-cell extravasation.ConclusionAltogether, we show that iRGD-anti-CD3 modification is an innovative and bifunctional strategy to overcome major bottlenecks in adoptive cell therapy. Moreover, we demonstrate that combination with PD-1 blockade can further improve antitumor efficacy of iRGD-anti-CD3-modified T cells.

NFATc3 regulates the transcription of genes involved in T-cell activation and angiogenesis

Blood ◽  
2011 ◽  
Vol 118 (3) ◽  
pp. 795-803 ◽  
Author(s):  
Katia Urso ◽  
Arantzazu Alfranca ◽  
Sara Martínez-Martínez ◽  
Amelia Escolano ◽  
Inmaculada Ortega ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Target Genes ◽  
Gene Knockout ◽  
Activated T Cells ◽  
Knock Down ◽  
And Function

Abstract The nuclear factor of activated T cells (NFAT) family of transcription factors plays important roles in many biologic processes, including the development and function of the immune and vascular systems. Cells usually express more than one NFAT member, raising the question of whether NFATs play overlapping roles or if each member has selective functions. Using mRNA knock-down, we show that NFATc3 is specifically required for IL2 and cyclooxygenase-2 (COX2) gene expression in transformed and primary T cells and for T-cell proliferation. We also show that NFATc3 regulates COX2 in endothelial cells, where it is required for COX2, dependent migration and angiogenesis in vivo. These results indicate that individual NFAT members mediate specific functions through the differential regulation of the transcription of target genes. These effects, observed on short-term suppression by mRNA knock-down, are likely to have been masked by compensatory effects in gene-knockout studies.

scholarly journals TRPM2 Is Not Required for T-Cell Activation and Differentiation

2022 ◽  
Vol 12 ◽  
Author(s):  
Niels C. Lory ◽  
Mikolaj Nawrocki ◽  
Martina Corazza ◽  
Joanna Schmid ◽  
Valéa Schumacher ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transient Receptor Potential ◽  
Cell Function ◽  
Intestinal Inflammation ◽  
Activation Markers

Antigen recognition by the T-cell receptor induces a cytosolic Ca2+ signal that is crucial for T-cell function. The Ca2+ channel TRPM2 (transient receptor potential cation channel subfamily M member 2) has been shown to facilitate influx of extracellular Ca2+ through the plasma membrane of T cells. Therefore, it was suggested that TRPM2 is involved in T-cell activation and differentiation. However, these results are largely derived from in vitro studies using T-cell lines and non-physiologic means of TRPM2 activation. Thus, the relevance of TRPM2-mediated Ca2+ signaling in T cells remains unclear. Here, we use TRPM2-deficient mice to investigate the function of TRPM2 in T-cell activation and differentiation. In response to TCR stimulation in vitro, Trpm2-/- and WT CD4+ and CD8+ T cells similarly upregulated the early activation markers NUR77, IRF4, and CD69. We also observed regular proliferation of Trpm2-/- CD8+ T cells and unimpaired differentiation of CD4+ T cells into Th1, Th17, and Treg cells under specific polarizing conditions. In vivo, Trpm2-/- and WT CD8+ T cells showed equal specific responses to Listeria monocytogenes after infection of WT and Trpm2-/- mice and after transfer of WT and Trpm2-/- CD8+ T cells into infected recipients. CD4+ T-cell responses were investigated in the model of anti-CD3 mAb-induced intestinal inflammation, which allows analysis of Th1, Th17, Treg, and Tr1-cell differentiation. Here again, we detected similar responses of WT and Trpm2-/- CD4+ T cells. In conclusion, our results argue against a major function of TRPM2 in T-cell activation and differentiation.

scholarly journals 702 TJ-CD4B (ABL111), a Claudin18.2-targeted 4-1BB tumor engager induces potent tumor-dependent immune response without dose-limiting toxicity in preclinical studies

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A730-A730
Author(s):  
Wenqing Jiang ◽  
Zhengyi Wang ◽  
Zhen Sheng ◽  
Jaeho Jung ◽  
Taylor Guo
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Gene Expression Analysis ◽  
Cell Activation ◽  
Clinical Development ◽  
Cynomolgus Monkeys ◽  
Anti Tumor Activity

Background4-1BB (CD137) is a co-stimulatory receptor that stimulates the function of multiple immune cells. Its ability to induce potent anti-tumor activity makes 4-1BB an attractive target for immuno-oncology. However, clinical development of a monospecific 4-1BB agonistic antibody has been hampered by dose-limiting hepatic toxicities. To minimize systemic toxicities, we have developed a novel Claudin18.2 (CLDN18.2) x 4-1BB bispecific antibody, TJ-CD4B (ABL111) that stimulates 4-1BB pathway only when it engages with Claudin 18.2, a tumor-associated antigen specifically expressed in gastrointestinal cancers. TJ-CD4B (ABL111) is now being evaluated in patients with advanced solid tumors in a first-in-human trial (NCT04900818).MethodsTJ-CD4B (ABL111) was evaluated in vivo using the human 4-1BB knock-in mice bearing CLDN18.2 expressing MC38 tumor cells. Pharmacodynamic effects upon treatment were characterized in tumor tissue and blood. Immunophenotyping of the tumor microenvironment (TME) and peripheral blood was performed by flow cytometry. Soluble biomarkers were measured using Luminex-based multiplex assay. In-depth gene expression analysis was performed on primary human CD8+ T cells that were co-cultured with CLDN18.2 expressing cells in the presence of anti-CD3 using NanoString nCounter®. Pharmacokinetic (PK) and toxicity study were performed in cynomolgus monkeys.ResultsTJ-CD4B (ABL111) elicited complete tumor regression in 13 out of 18 MC38 tumor bearing mice given at a dose above 2 mg/kg. Dose-dependent anti-tumor activity was associated with enhanced T cell activation in TME and expansion of memory T cells in the peripheral blood. Increased CD8+ T cells number and proliferation were observed in both tumor nest and surrounding stroma while the level of soluble 4-1BB in the serum was also elevated in response to the treatment. In vitro gene expression analysis by Nanostring revealed TJ-CD4B(ABL111) effectively activated immune pathways characterized by IFN?-signaling and T cell inflammation. Preclinically, TJ-CD4B was well tolerated at the repeated doses up to 100 mg/kg/wk in cynomolgus monkeys without the adverse influence on the liver function which is generally affected by 4-1BB activation. Besides, no cytokine release or immune activation was observed in the periphery.ConclusionsTJ-CD4B (ABL111) is a novel CLDN18.2 dependent 4-1BB bispecific agonist antibody that induced T cell activation and memory response in tumor with CLDN18.2 expression, leading to a strong anti-tumor activity in vivo. TJ-CD4B did not induce systemic immune response nor hepatic toxicity due to the CLDN18.2 dependent 4-1BB stimulation. These data warrant the current clinical development in phase I trial to validate the safety properties and tumor specific responses.

scholarly journals 206 The development of ‘chimeric CD3e fusion protein’ and ‘anti-CD3-based bispecific T cell activating element’ engineered T (CAB-T) cells for the treatment of solid malignancies

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A217-A217
Author(s):  
Andy Tsun ◽  
Zhiyuan Li ◽  
Zhenqing Zhang ◽  
Weifeng Huang ◽  
Shaogang Peng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Fusion Protein ◽  
T Cell Activation ◽  
Cell Activation ◽  
In Vivo Studies ◽  
Cytokine Release ◽  
Car T Cells ◽  
Car T

BackgroundCancer immunotherapy has achieved unprecedented success in the complete remission of hematological tumors. However, serious or even fatal clinical side-effects have been associated with CAR-T therapies to solid tumors, which mainly include cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), macrophage activation syndrome, etc. Furthermore, CAR-T therapies have not yet demonstrated significant clinical efficacy for the treatment of solid tumors. Here, we present a novel T cell therapeutic platform: a Chimeric CD3e fusion protein and anti-CD3-based bispecific T cell activating element (BiTA) engineered T (CAB-T) cells, which target tumor antigens via the secretion of BiTAs that act independently of MHC interactions. Upon BiTA secretion, CAB-T cells can simultaneously achieve anti-tumor cytotoxic effects from the CAB-T cells and simultaneously activate bystander T cells.MethodsCAB-T cells were generated by co-expressing a chimeric CD3e fusion protein and an anti-CD3-based bispecific T cell activating element. The chimeric CD3e contains the extracellular domain of CD3e, a CD8 transmembrane domain, 4-1BB costimulatory domain, CD3z T cell activation domain and a FLAG tag, while the BiTA element includes a tumor antigen targeting domain fused with an anti-CD3 scFv domain and a 6x His-tag. CAR-T cells were generated as a control. Cytokine release activity, T cell activation and exhaustion markers, T cell killing activity and T cell differentiation stages were analysed. We also tested their tumor growth inhibition activity, peripheral and tumor tissue distribution, and their safety-profiles in humanized mouse models.ResultsCAB-T cells have similar or better in vitro killing activity compared with their CAR-T counterparts, with lower levels of cytokine release (IL-2 and IFNγ). CAB-T cells also showed lower levels of exhaustion markers (PD-1, LAG-3 and TIM-3), and higher ratios of naive/Tscm and Tcm T cell populations, after co-culture with their target tumor cells (48h). In in vivo studies, CAIX CAB-T and HER2 CAB-T showed superior anti-tumor efficacy and tumor tissue infiltration activity over their corresponding CAR-T cells. For CLDN18.2 CAB-T cells, similar in vivo anti-tumor efficacy was observed compared to CAR-T after T cell infusion, but blood glucose reduction and animal mortality was observed in the mice administered with CAR-T cells.ConclusionsThe advantages of CAB-T in in vitro and in vivo studies may result from TCR signal activation of both the engineered CAB-T cells and the non-engineered bystander T cells via cross-bridging by the secreted BiTA molecules, thus offering superior anti-tumor efficacy with a potential better safety-profile compared to conventional CAR-T platforms.

scholarly journals Inconsistent Reversal of HIV-1 Latency Ex Vivo by Antigens of HIV-1, CMV, and Other Infectious Agents

2020 ◽  
Author(s):  
Thomas Vollbrecht ◽  
Aaron O. Angerstein ◽  
Bryson Menke ◽  
Nikesh M. Kumar ◽  
Michelli Faria Oliveira ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Ex Vivo ◽  
Latent Reservoir ◽  
Antigen Specificity ◽  
Pcr Assay ◽  
Hiv 1

Abstract BackgroundA reservoir of replication-competent but latent virus is the main obstacle to a cure for HIV-infection. Much of this reservoir resides in memory CD4 T cells. We hypothesized that these cells can be reactivated with antigens from HIV and other common pathogens to reverse latency. ResultsWe obtained mononuclear cells from the peripheral blood of antiretroviral-treated patients with suppressed viremia. We tested pools of peptides and proteins derived from HIV and from other pathogens including CMV for their ability to reverse latency ex vivo by activation of memory responses. We assessed activation of the CD4 T cells by measuring the up-regulation of cell-surface CD69. We assessed HIV-expression using two assays: a real-time PCR assay for virion-associated viral RNA and a droplet digital PCR assay for cell-associated, multiply spliced viral mRNA. Reversal of latency occurred in a minority of cells from some participants, but no single antigen induced HIV-expression ex vivo consistently. When reversal of latency was induced by a specific peptide pool or protein, the extent was proportionally greater than that of T cell activation. ConclusionsIn this group of patients in whom antiretroviral therapy was started during chronic infection, the latent reservoir does not appear to consistently reside in CD4 T cells of a predominant antigen-specificity. Peptide-antigens reversed HIV-latency ex vivo with modest and variable activity. When latency was reversed by specific peptides or proteins, it was proportionally greater than the extent of T cell activation, suggesting partial enrichment of the latent reservoir in cells of specific antigen-reactivity.

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