scholarly journals Jejunal Brush Border Microvillous Alterations inGiardia muris-Infected Mice: Role of T Lymphocytes and Interleukin-6

2000 ◽  
Vol 68 (6) ◽  
pp. 3412-3418 ◽  
Author(s):  
K. G.-E. Scott ◽  
M. R. Logan ◽  
G. M. Klammer ◽  
D. A. Teoh ◽  
A. G. Buret
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Surface Area ◽  
Nude Mice ◽  
Brush Border ◽  
Interleukin 6 ◽  
Parasite Load ◽  
Diffuse Loss

ABSTRACT Intestinal colonization with the protozoan Giardiacauses diffuse brush border microvillous alterations and disaccharidase deficiencies, which in turn are responsible for intestinal malabsorption and maldigestion. The role of T cells and/or cytokines in the pathogenesis of Giardia-induced microvillous injury remains unclear. The aim of this study was to assess the role of T cells and interleukin-6 (IL-6) in the brush border pathophysiology of acute murine giardiasis in vivo. Athymic nude (nu−/nu−) CD-1 mice and isogenic immunocompetent (nu+/nu+) CD-1 mice (4 weeks old) received an axenic Giardia muris trophozoite inoculum or vehicle (control) via orogastric gavage. Weight gain and food intake were assessed daily. On day 6, segments of jejunum were assessed for parasite load, brush border ultrastructure, IL-6 content, maltase and sucrase activities, villus-crypt architecture, and intraepithelial lymphocyte (IEL) infiltration. Despite similar parasitic loads on day 6, infected immunocompetent animals, but not infected nude mice, showed a diffuse loss of brush border microvillous surface area, which was correlated with a significant reduction in maltase and sucrase activities and a decrease in jejunal IL-6 concentration. In both athymic control and infected mice, jejunal brush border surface area and disaccharidases were high, but levels of tissue IL-6 were low and comparable to the concentration measured in immunocompetent infected animals. In both immunocompetent and nude mice, infection caused a small but significant increase in the numbers of IELs. These findings suggest that the enterocyte brush border injury and malfunction seen in giardiasis is, at least in part, mediated by thymus-derived T lymphocytes and that suppressed jejunal IL-6 does not necessarily accompany microvillous shortening.

scholarly journals Influenza virus-specific CD4+ T helper type 2 T lymphocytes do not promote recovery from experimental virus infection.

1994 ◽  
Vol 180 (4) ◽  
pp. 1273-1282 ◽  
Author(s):  
M B Graham ◽  
V L Braciale ◽  
T J Braciale
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Lymphocytes ◽  
Cd4 T Cells ◽  
Primary Role ◽  
T Helper ◽  
Helper Type

T lymphocytes play a primary role in recovery from viral infections and in antiviral immunity. Although viral-specific CD8+ and CD4+ T cells have been shown to be able to lyse virally infected targets in vitro and promote recovery from lethal infection in vivo, the role of CD4+ T lymphocytes and their mechanism(s) of action in viral immunity are not well understood. The ability to further dissect the role that CD4+ T cells play in the immune response to a number of pathogens has been greatly enhanced by evidence for more extensive heterogeneity among the CD4+ T lymphocytes. To further examine the role of CD4+ T cells in the immune response to influenza infection, we have generated influenza virus-specific CD4+ T cell clones from influenza-primed BALB/c mice with differential cytokine secretion profiles that are defined as T helper type 1 (Th1) clones by the production of interleukin 2 (IL-2) and interferon gamma (IFN-gamma), or as Th2 clones by the production of IL-4, IL-5, and IL-10. Our studies have revealed that Th1 clones are cytolytic in vitro and protective against lethal challenge with virus in vivo, whereas Th2 clones are noncytolytic and not protective. Upon further evaluation of these clonal populations we have shown that not only are the Th2 clones nonprotective, but that pulmonary pathology is exacerbated as compared with control mice as evidenced by delayed viral clearance and massive pulmonary eosinophilia. These data suggest that virus-specific CD4+ T cells of the Th2 subset may not play a primary role in virus clearance and recovery and may lead to immune mediated potentiation of injury.

scholarly journals Tissue-Specific Autoregulation of thestat3 Gene and Its Role in Interleukin-6-Induced Survival Signals in T Cells

2001 ◽  
Vol 21 (19) ◽  
pp. 6615-6625 ◽  
Author(s):  
Masahiro Narimatsu ◽  
Hisoka Maeda ◽  
Shousaku Itoh ◽  
Toru Atsumi ◽  
Takuya Ohtani ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Interleukin 6 ◽  
Target Genes ◽  
Gene Activation ◽  
Tissue Specific ◽  
Direct Target ◽  
Responsive Element ◽  
Transcription 3

ABSTRACT Signal transducer and activator of transcription 3 (STAT3) mediates signals of various growth factors and cytokines, including interleukin-6 (IL-6). In certain IL-6-responsive cell lines, thestat3 gene is autoregulated by STAT3 through a composite IL-6 response element in its promoter that contains a STAT3-binding element (SBE) and a cyclic AMP-responsive element. To reveal the nature and roles of the stat3 autoregulation in vivo, we generated mice that harbor a mutation in the SBE (stat3 mSBE ). The intact SBE was crucial for IL-6-induced stat3 gene activation in the spleen, especially in the red pulp region, the kidney, and both mature and immature T lymphocytes. The SBE was not required, however, for IL-6-induced stat3 gene activation in hepatocytes. T lymphocytes from the stat3 mSBE/mSBE mice were more susceptible to apoptosis despite the presence of IL-6 than those from wild-type mice. Consistent with this, IL-6-dependent activation of the Pim-1 and junB genes, direct target genes for STAT3, was attenuated in T lymphocytes of thestat3 mSBE/mSBE mice. Thus, the tissue-specific autoregulation of the stat3 gene operates in vivo and plays a role in IL-6-induced antiapoptotic signaling in T cells.

scholarly journals ICAMs Redistributed by Chemokines to Cellular Uropods as a Mechanism for Recruitment of T Lymphocytes

1997 ◽  
Vol 137 (2) ◽  
pp. 493-508 ◽  
Author(s):  
Miguel Angel del Pozo ◽  
Carlos Cabañas ◽  
María C. Montoya ◽  
Ann Ager ◽  
Paloma Sánchez-Mateos ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Fold Increase ◽  
Time Lapse ◽  
Cell Recruitment ◽  
T Cell Migration ◽  
Physiological Relevance ◽  
Amplification System

The recruitment of leukocytes from the bloodstream is a key step in the inflammatory reaction, and chemokines are among the main regulators of this process. During lymphocyte–endothelial interaction, chemokines induce the polarization of T lymphocytes, with the formation of a cytoplasmic projection (uropod) and redistribution of several adhesion molecules (ICAM-1,-3, CD43, CD44) to this structure. Although it has been reported that these cytokines regulate the adhesive state of integrins in leukocytes, their precise mechanisms of chemoattraction remain to be elucidated. We have herein studied the functional role of the lymphocyte uropod. Confocal microscopy studies clearly showed that cell uropods project away from the cell bodies of adhered lymphocytes and that polarized T cells contact other T cells through the uropod structure. Time-lapse videomicroscopy studies revealed that uropod-bearing T cells were able, through this cellular projection, to contact, capture, and transport additional bystander T cells. Quantitative analysis revealed that the induction of uropods results in a 5–10-fold increase in cell recruitment. Uropod-mediated cell recruitment seems to have physiological relevance, since it was promoted by both CD45R0+ peripheral blood memory T cells as well as by in vivo activated lymphocytes. Additional studies showed that the cell recruitment mediated by uropods was abrogated with antibodies to ICAM-1, -3, and LFA-1, whereas mAb to CD43, CD44, CD45, and L-selectin did not have a significant effect, thus indicating that the interaction of LFA-1 with ICAM-1 and -3 appears to be responsible for this process. To determine whether the increment in cell recruitment mediated by uropod may affect the transendothelial migration of T cells, we carried out chemotaxis assays through confluent monolayers of endothelial cells specialized in lymphocyte extravasation. An enhancement of T cell migration was observed under conditions of uropod formation, and this increase was prevented by incubation with either blocking anti– ICAM-3 mAbs or drugs that impair uropod formation. These data indicate that the cell interactions mediated by cell uropods represent a cooperative mechanism in lymphocyte recruitment, which may act as an amplification system in the inflammatory response.

scholarly journals Ahr-Foxp3-RORγt axis controls gut homing of CD4+ T cells by regulating GPR15

2020 ◽  
Vol 5 (48) ◽  
pp. eaaz7277 ◽  
Author(s):  
Lifeng Xiong ◽  
Joseph W. Dean ◽  
Zheng Fu ◽  
Kristen N. Oliff ◽  
John W. Bostick ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Immune Homeostasis ◽  
Open Chromatin ◽  
Homing Receptor ◽  
Aryl Hydrocarbon

The orphan chemoattractant receptor GPR15 is important for homing T lymphocytes to the large intestine, thereby maintaining intestinal immune homeostasis. However, the molecular mechanisms underlying the regulation of GPR15 expression remain elusive. Here, we show a central role of the aryl hydrocarbon receptor (Ahr) in promoting GPR15 expression in both mice and human, thus gut homing of T lymphocytes. Mechanistically, Ahr directly binds to open chromatin regions of the Gpr15 locus to enhance its expression. Ahr transcriptional activity in directing GPR15 expression was modulated by two transcription factors, Foxp3 and RORγt, both of which are expressed preferentially by gut regulatory T cells (Tregs) in vivo. Specifically, Foxp3 interacted with Ahr and enhanced Ahr DNA binding at the Gpr15 locus, thereby promoting GPR15 expression. In contrast, RORγt plays an inhibitory role, at least in part, by competing with Ahr binding to the Gpr15 locus. Our findings thus demonstrate a key role for Ahr in regulating Treg intestinal homing under the steady state and during inflammation and the importance of Ahr-RORγt-Foxp3 axis in regulating gut homing receptor GPR15 expression by lymphocytes.

TCR and DNAM Dependent Lysis of Acute Monocytic Leukemia (AMoL) by Vg9Vd2 T Lymphocytes.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1041-1041
Author(s):  
Julie Gertner-Dardenne ◽  
Eloise Perrot ◽  
Thomas Prebet ◽  
Aude Charbonnier ◽  
Helene Sicard ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Stem Cell ◽  
T Lymphocytes ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
Acute Myeloid

Abstract Abstract 1041 Poster Board I-63 BACKGROUNd: Compelling evidences have demonstrated the role of the immune system in the control of acute myeloid leukemia (AML). So far, T cells and natural killer (NK) cells are the major immune effectors shown to be involved in AML control. The graft-versus-leukemia (GVL) effect following allogenic stem cell transplantation as well as donor lymphocyte infusions indicate that T lymphocytes can control and eliminate AML cells. Leukemia-specific antigenic peptides have been characterized (proteinase-3 and Wilms tumor 1 protein) and serve as targets for peptide-based vaccine trials in AML. Allogenic NK cells have anti-leukemic activity as shown by killer cell inhibitory receptor (KIR)-mismatched haplo-identical stem cell transplantation. Less is known regarding the role of gd T cells in the control of AML. Recently the reconstitution of Vd1 T lymphocytes post transplantation has been shown to correlate with a better prognosis. In the present study, we have analyzed gd T cells in patients with AML and in a mouse model of human AML and focused on (Vg9) Vd2 T cells, the main subset of circulating gd T cells with anti-neoplastic activity. Human Vg9Vd2 T lymphocytes can be activated by nonpeptidic antigens such as the mevalonate pathway-derived isopentenyl pyrophosphate or synthetic phosphoantigen such as bromohydrin pyrophosphate (BrHPP). This population may be suitable for the adoptive immunotherapy of acute myeloid leukemia (AML). However little is known about the frequency, the function and the mechanisms underlying Vg9Vd2 T-cell recognition of AML. We have focused this study on AMoL which are targets of NK and ab T cells. OBJECTIVE OF THE STUDY to describe Vg9Vd2 T cells in patients with AML and investigate their ability to induce an effective cytotoxic response against autologous AML blast in vitro and in vivo. EXPERIMENTAL PROCEDURe: We compared the phenotype and the absolute circulating Vg9Vd2 T cell levels in the blood and the bone marrow (BM) in 12 patients with AMoL (FAB AML-M4 and -M5) and 12 healthy volunteers (HV) using multi parametric flow cytometry. All patients and volunteers gave written informed consent. Vg9Vd2 T cells of AML patient were expanded ex vivo using BrHPP or Zoledronic acid plus IL2. The functions of expanded Vg9Vd2 T cells were assessed in vitro by their cytotoxicity against leukemic blasts (CD107a staining, 51Cr assay) and in vivo in immunodeficient mice transplanted with human AML cell line (U937). In these experiments, the ability of adoptively transferred Vg9Vd2 T cells to migrate into BM and improve mice survival was assessed after i.v. infusion of U937 cells into healthy female NOD-SCID, common _-chain knockout mice (NOG mice). Mice were then treated twice i.v. with 40.106 Vg9Vd2 T cells. RESULTs: Vg9Vd2 T lymphocytes are present in the blood as well as BM of AMoL patients at a lower frequency as compared to HV (median 2.07/μl vs 34/μL respectively P<0.001). Vg9Vd2 T lymphocytes from AML patients are endowed with in vitro proliferation in response to BrHPP or Zoledronic acid plus IL2 but lower than HV (fold increase median 33 versus 69, P=0.051). Expanded Vg9Vd2 express activation markers (CD69 and CCR5) and exhibit an effector/memory phenotype (CD45RA- CD27-). Their lytic potential toward autologous AML blast was equivalent to those of HV by 51Cr experiments and CD107a staining and involves the perforin-granzyme pathway. Their activity depends on both TCRVd2 and DNAX accessory molecule-1 (DNAM-1) as demonstrated by antibody blockade. In vivo data show that, upon sacrifice, Vg9Vd2 were detected in BM, spleen and blood of mice. Preliminary Kaplan-Meier analysis of pooled cohorts of Vg9Vd2-treated and untreated mice reveals that mice receiving Vg9Vd2 T cells displayed superior survival compared with untreated controls (P=0.0047). CONCLUSIOn: Altogether, our data indicate that Vg9Vd2 T cells are decreased in AML patients and have a more limited expansion potential. However, they are able to kill autologous AML blast upon stimulation in a TCRVd2 as well as the DNAM-1 receptor dependent manner. These results provide a rationale for the clinical evaluation of adoptive transfer of ex vivo expanded allogenic Vg9Vd2T cells or direct activation of Vg9Vd2T cells with IL2 + phosphoantigens in patients with AML. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Metabolic radiolabeling and in vivo PET imaging of cytotoxic T lymphocytes to guide combination adoptive cell transfer cancer therapy

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Dehua Lu ◽  
Yanpu Wang ◽  
Ting Zhang ◽  
Feng Wang ◽  
Kui Li ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Solid Tumors ◽  
Cytotoxic T Lymphocytes ◽  
Pet Imaging ◽  
Stage Migration ◽  
Cell Transfer ◽  
Tumor Infiltration ◽  
Antitumor Effects

Abstract Background Adoptive T cell transfer-based immunotherapy yields unsatisfactory results in the treatment of solid tumors, partially owing to limited tumor infiltration and the immunosuppressive microenvironment in solid tumors. Therefore, strategies for the noninvasive tracking of adoptive T cells are critical for monitoring tumor infiltration and for guiding the development of novel combination therapies. Methods We developed a radiolabeling method for cytotoxic T lymphocytes (CTLs) that comprises metabolically labeling the cell surface glycans with azidosugars and then covalently conjugating them with 64Cu-1,4,7-triazacyclononanetriacetic acid-dibenzo-cyclooctyne (64Cu-NOTA-DBCO) using bioorthogonal chemistry. 64Cu-labeled control-CTLs and ovalbumin-specific CTLs (OVA-CTLs) were tracked using positron emission tomography (PET) in B16-OVA tumor-bearing mice. We also investigated the effects of focal adhesion kinase (FAK) inhibition on the antitumor efficacy of OVA-CTLs using a poly(lactic-co-glycolic) acid (PLGA)-encapsulated nanodrug (PLGA-FAKi). Results CTLs can be stably radiolabeled with 64Cu with a minimal effect on cell viability. PET imaging of 64Cu-OVA-CTLs enables noninvasive mapping of their in vivo behavior. Moreover, 64Cu-OVA-CTLs PET imaging revealed that PLGA-FAKi induced a significant increase in OVA-CTL infiltration into tumors, suggesting the potential for a combined therapy comprising OVA-CTLs and PLGA-FAKi. Further combination therapy studies confirmed that the PLGA-FAKi nanodrug markedly improved the antitumor effects of adoptive OVA-CTLs transfer by multiple mechanisms. Conclusion These findings demonstrated that metabolic radiolabeling followed by PET imaging can be used to sensitively profile the early-stage migration and tumor-targeting efficiency of adoptive T cells in vivo. This strategy presents opportunities for predicting the efficacy of cell-based adoptive therapies and for guiding combination regimens. Graphic Abstract

scholarly journals Absence of Bim sensitizes mice to experimental Trypanosoma cruzi infection

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Marcela Hernández-Torres ◽  
Rogério Silva do Nascimento ◽  
Monica Cardozo Rebouças ◽  
Alexandra Cassado ◽  
Kely Catarine Matteucci ◽  
...  
Keyword(s):  
T Cells ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Parasite Load ◽  
Peritoneal Macrophages ◽  
T Cell Response ◽  
No Production ◽  
Similar Reduction ◽  
Ifn Γ

AbstractChagas disease is a life-threatening disorder caused by the protozoan parasite Trypanosoma cruzi. Parasite-specific antibodies, CD8+ T cells, as well as IFN-γ and nitric oxide (NO) are key elements of the adaptive and innate immunity against the extracellular and intracellular forms of the parasite. Bim is a potent pro-apoptotic member of the Bcl-2 family implicated in different aspects of the immune regulation, such as negative selection of self-reactive thymocytes and elimination of antigen-specific T cells at the end of an immune response. Interestingly, the role of Bim during infections remains largely unidentified. To explore the role of Bim in Chagas disease, we infected WT, Bim+/−, Bim−/− mice with trypomastigotes forms of the Y strain of T. cruzi. Strikingly, our data revealed that Bim−/− mice exhibit a delay in the development of parasitemia followed by a deficiency in the control of parasite load in the bloodstream and a decreased survival compared to WT and Bim+/− mice. At the peak of parasitemia, peritoneal macrophages of Bim−/− mice exhibit decreased NO production, which correlated with a decrease in the pro-inflammatory Small Peritoneal Macrophage (SPM) subset. A similar reduction in NO secretion, as well as in the pro-inflammatory cytokines IFN-γ and IL-6, was also observed in Bim−/− splenocytes. Moreover, an impaired anti-T. cruzi CD8+ T-cell response was found in Bim−/− mice at this time point. Taken together, our results suggest that these alterations may contribute to the establishment of a delayed yet enlarged parasitic load observed at day 9 after infection of Bim−/− mice and place Bim as an important protein in the control of T. cruzi infections.

scholarly journals Gastric Hyperplasia and Increased Proliferative Responses of Lymphocytes in Mice Lacking the COOH-terminal Ankyrin Domain of NF-κB2

1997 ◽  
Vol 186 (7) ◽  
pp. 999-1014 ◽  
Author(s):  
Hideaki Ishikawa ◽  
Daniel Carrasco ◽  
Estefania Claudio ◽  
Rolf-Peter Ryseck ◽  
Rodrigo Bravo
Keyword(s):  
T Cells ◽  
Lymphocyte Proliferation ◽  
Cytokine Production ◽  
Cell Types ◽  
Homozygous Deletion ◽  
Binding Activity ◽  
Activated T Cells ◽  
Physiological Relevance

The nfkb2 gene encodes the p100 precursor which produces the p52 protein after proteolytic cleavage of its COOH-terminal domain. Although the p52 product can act as an alternative subunit of NF-κB, the p100 precursor is believed to function as an inhibitor of Rel/NF-κB activity by cytoplasmic retention of Rel/NF-κB complexes, like other members of the IκB family. However, the physiological relevance of the p100 precursor as an IκB molecule has not been understood. To assess the role of the precursor in vivo, we generated, by gene targeting, mice lacking p100 but still containing a functional p52 protein. Mice with a homozygous deletion of the COOH-terminal ankyrin repeats of NF-κB2 (p100−/−) had marked gastric hyperplasia, resulting in early postnatal death. p100−/− animals also presented histopathological alterations of hematopoietic tissues, enlarged lymph nodes, increased lymphocyte proliferation in response to several stimuli, and enhanced cytokine production in activated T cells. Dramatic induction of nuclear κB–binding activity composed of p52-containing complexes was found in all tissues examined and also in stimulated lymphocytes. Thus, the p100 precursor is essential for the proper regulation of p52-containing Rel/NF-κB complexes in various cell types and its absence cannot be efficiently compensated for by other IκB proteins.

scholarly journals A reassessment of the role of B7-1 expression in tumor rejection.

1995 ◽  
Vol 182 (5) ◽  
pp. 1415-1421 ◽  
Author(s):  
T C Wu ◽  
A Y Huang ◽  
E M Jaffee ◽  
H I Levitsky ◽  
D M Pardoll
Keyword(s):  
T Cells ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Tumor Rejection ◽  
Type B ◽  
Wild Type ◽  
Systemic Immunity ◽  
Murine Tumor

Introduction of the B7-1 gene into murine tumor cells can result in rejection of the B7-1 transductants and, in some cases, systemic immunity to subsequent challenge with the nontransduced tumor cells. These effects have been largely attributed to the function of B7-1 as a costimulator in directly activating tumor specific, major histocompatibility class I-restricted CD8+ T cells. We examined the role of B7-1 expression in the direct rejection as well as in the induction of systemic immunity to a nonimmunogenic murine tumor. B-16 melanoma cells with high levels of B7-1 expression did not grow in C57BL/6 recipient mice, while wild-type B-16 cells and cells with low B7-1 expression grew progressively within 21 d. In mixing experiments with B7-1hi and wild-type B-16 cells, tumors grew out in vivo even when a minority of cells were B7-1-. Furthermore, the occasional tumors that grew out after injection of 100% B-16 B7-1hi cells showed markedly decreased B7-1 expression. In vivo antibody depletions showed that NK1.1 and CD8+ T cells, but not CD4+ T cells, were essential for the in vivo rejection of tumors. Animals that rejected B-16 B7-1hi tumors did not develop enhanced systemic immunity against challenge with wild-type B-16 cells. These results suggest that a major role of B7-1 expression by tumors is to mediate direct recognition and killing by natural killer cells. With an intrinsically nonimmunogenic tumor, this direct killing does not lead to enhanced systemic immunity.

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