scholarly journals Depletion of CD8+ T Cells In Vivo Impairs Host Defense of Mice Resistant and Susceptible to Pulmonary Paracoccidioidomycosis

2000 ◽  
Vol 68 (1) ◽  
pp. 352-359 ◽  
Author(s):  
Luz E. Cano ◽  
Lúcia M. Singer-Vermes ◽  
Tania A. Costa ◽  
José O. Mengel ◽  
Cynthia F. Xidieh ◽  
...  
Keyword(s):  
T Cells ◽  
Monoclonal Antibodies ◽  
Paracoccidioides Brasiliensis ◽  
Delayed Type Hypersensitivity ◽  
Mouse Strains ◽  
Fungal Load ◽  
Granulomatous Lesions ◽  
Selective Depletion

ABSTRACT Using a pulmonary model of infection, we demonstrated previously that A/Sn and B10.A mice are, respectively, resistant and susceptible to Paracoccidioides brasiliensis infection. Employing the same experimental model, we examined herein the role of CD8+ T cells in the course of paracoccidioidomycosis. Treatment with anti-CD8 monoclonal antibodies caused a selective depletion of pulmonary and splenic CD8+ T cells in both mouse strains. The number of pulmonary CD4+ T cells and immunoglobulin-positive cells was independent of the number of CD8+ T cells. In susceptible mice, the loss of CD8+ T cells by in vivo treatment with anti-CD8 monoclonal antibodies impaired the clearance of yeasts from the lungs and increased the fungal dissemination to the liver and spleen. The same treatment in resistant mice increased fungal dissemination to extrapulmonary tissues but did not alter the pulmonary fungal load. Furthermore, CD8+ T-cell depletion did not modify delayed-type hypersensitivity reactions of A/Sn mice but increased these reactions in B10.A mice. The production of P. brasiliensis-specific antibodies by resistant and susceptible mice depleted of CD8+ T cells was similar to that of mice given control antibody. Histopathologically, depletion of CD8+ T cells did not disorganize the focal granulomatous lesions developed by both mouse strains. These results indicate that CD8+ T cells are necessary for optimal clearance of the fungus from tissues of mice infected with P. brasiliensisand demonstrate more prominent protective activity by those cells in the immune responses mounted by susceptible animals.

scholarly journals Critical Contribution of Ox40 Ligand to T Helper Cell Type 2 Differentiation in Experimental Leishmaniasis

2000 ◽  
Vol 191 (2) ◽  
pp. 375-380 ◽  
Author(s):  
Hisaya Akiba ◽  
Yasushi Miyahira ◽  
Machiko Atsuta ◽  
Kazuyoshi Takeda ◽  
Chiyoko Nohara ◽  
...  
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Leishmania Major ◽  
Critical Role ◽  
Flow Cytometric Analysis ◽  
Th2 Cells ◽  
Mouse Strains ◽  
T Helper

Infection of inbred mouse strains with Leishmania major is a well characterized model for analysis of T helper (Th)1 and Th2 cell development in vivo. In this study, to address the role of costimulatory molecules CD27, CD30, 4-1BB, and OX40, which belong to the tumor necrosis factor receptor superfamily, in the development of Th1 and Th2 cells in vivo, we administered monoclonal antibody (mAb) against their ligands, CD70, CD30 ligand (L), 4-1BBL, and OX40L, to mice infected with L. major. Whereas anti-CD70, anti-CD30L, and anti–4-1BBL mAb exhibited no effect in either susceptible BALB/c or resistant C57BL/6 mice, the administration of anti-OX40L mAb abrogated progressive disease in BALB/c mice. Flow cytometric analysis indicated that OX40 was expressed on CD4+ T cells and OX40L was expressed on CD11c+ dendritic cells in the popliteal lymph nodes of L. major–infected BALB/c mice. In vitro stimulation of these CD4+ T cells showed that anti-OX40L mAb treatment resulted in substantially reduced production of Th2 cytokines. Moreover, this change in cytokine levels was associated with reduced levels of anti–L. major immunoglobulin (Ig)G1 and serum IgE. These results indicate that anti-OX40L mAb abrogated progressive leishmaniasis in BALB/c mice by suppressing the development of Th2 responses, substantiating a critical role of OX40–OX40L interaction in Th2 development in vivo.

scholarly journals Role of Complement Receptors in Uptake ofMycobacterium avium by Macrophages In Vivo: Evidence from Studies Using CD18-Deficient Mice

1999 ◽  
Vol 67 (9) ◽  
pp. 4912-4916 ◽  
Author(s):  
Luiz E. Bermudez ◽  
Joseph Goodman ◽  
Mary Petrofsky
Keyword(s):  
Mouse Strains ◽  
Histopathological Study ◽  
Intracellular Pathogen ◽  
Complement Receptors ◽  
Transmission Electron ◽  
Granulomatous Lesions ◽  
Deficient Mice

ABSTRACT Mycobacterium avium is an intracellular pathogen that has been shown to invade macrophages by using complement receptors in vitro, but mycobacteria released from one cell can enter a second macrophage by using receptors different from complement receptors. Infection of CD18 (β2 integrin) knockout mice and the C57 BL/6 control mice led to comparable levels of tissue infection at 1 day, 2 days, 1 week, and 3 weeks following administration of bacteria. A histopathological study revealed similar granulomatous lesions in the two mouse strains, with comparable numbers of organisms. In addition, transmission electron microscopy of spleen tissues from both strains of mice showed bacteria inside macrophages. Our in vivo findings support the hypothesis that M. avium in the host is likely to use receptors other than CR3 and CR4 receptors to enter macrophages with increased efficiency.

scholarly journals CD4+ T Cells Sustain Aggressive Chronic Lymphocytic Leukemia through a CD40L-Independent Mechanism

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 683-683
Author(s):  
Matteo Bellone ◽  
Paolo Dellabona ◽  
Arianna Calcinotto ◽  
Giulia Casorati ◽  
Alessandra Rovida ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Monoclonal Antibodies ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Membrane Bound

In Chronic Lymphocytic Leukemia (CLL), mature CD5+ B cells accumulate in lymphoid organs such as bone marrow and lymph nodes where they proliferate and expand within localized proliferation centers. In vitro and in vivo data suggest that survival and proliferation of CLL cells within proliferation centers may be also dependent on microenvironmental interactions originating from the surrounding cellular elements (e.g. monocyte-derived nurse-like cells, mesenchymal stromal cells, or CD4+ T lymphocytes), that deliver both membrane-bound and soluble signals to CLL cells. In particular, the role of CD4+ T cells in vivo is less defined and data in animal models are conflicting as they appear to sustain CLL clone expansion and survival through CD40L-CD40 interactions, though in approximately 40% of patients with CLL, aggressive leukemic clones appear to be independent of CD40 stimulation. We aimed at clarifying the role of CD4+ T lymphocytes taking advantage of the Eμ-TCL1 mouse model, which develops a disease that mimics aggressive, human CLL. To this aim, we generated genetically modified Eμ-TCL1 mice lacking either CD4+ T cells (TCL1+/+AB0), CD40 (TCL1+/+CD40-/-), or CD8+ T cells (TCL1+/+TAP-/-). In these mice, disease appearance and progression were monitored in lymphoid organs and blood by flow cytometry and immunohistochemistry analyses. Findings were confirmed by adoptive transfer of leukemic clones into mice either lacking CD4+ T cells, or CD40L, or treated with monoclonal antibodies depleting selected T cell populations, or blocking CD40L-CD40 interactions. Interestingly, we observed that CLL clones did not expand in mice either lacking or depleted of CD4+ T cells, thus confirming that CD4+ T cells are essential for CLL development in Eμ-TCL1 mice. On the contrary, in TCL1+/+TAP-/- mice, lacking CD8+ T cells, disease progression was accelerated, suggesting an anti-tumor activity exerted by this subset of T cells. Specificity of CD4+ T cells was marginal for CLL development, as leukemic clones developed regularly in transgenic mice whose CD4+ T cells had TCR with CLL-unrelated specificities. Similarly, TCL1+/+CD40-/- mice developed frank CLL with no differences compared to controls, as well as leukemic clones expanded when transferred into wild type mice treated with monoclonal antibodies blocking CD40, or into CD40L-/- mice, suggesting a dispensable role for CD40/CD40L stimulation in the development of murine CLL. Analysis of peritoneal fluid, spleen, lymph nodes and bone marrow showed similar CLL development in Eμ-TCL1 and TCL1+/+CD40-/- mice. In conclusion, our data demonstrates that CD8+ and CD4+ T cells exert opposite roles in CLL: CD8+ T cells restrain CLL progression, whereas CD4+ T cells support the expansion of CLL clones in Eμ-TCL1 mice through CD40-indipendent, and apparently non-cognate mechanisms. Further studies are warranted to dissect the nature of the molecules, either soluble or membrane-bound, responsible for the interactions occurring between CD4+ T cells and CLL B cells fueling the onset and expansion of CLL cells. Disclosures Ghia: AbbVie: Consultancy, Honoraria, Research Funding; Acerta/AstraZeneca: Consultancy, Honoraria; ArQule: Consultancy, Honoraria; BeiGene: Consultancy, Honoraria; Dynamo: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Juno/Celgene: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Novartis: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy.

scholarly journals Resolution of Secondary Chlamydia trachomatis Genital Tract Infection in Immune Mice with Depletion of Both CD4+ and CD8+ T cells

2001 ◽  
Vol 69 (4) ◽  
pp. 2643-2649 ◽  
Author(s):  
Sandra G. Morrison ◽  
Richard P. Morrison
Keyword(s):  
T Cells ◽  
B Cells ◽  
Chlamydia Trachomatis ◽  
Tract Infection ◽  
Genital Tract ◽  
Delayed Type Hypersensitivity ◽  
Predominant Role ◽  
Genital Tract Infection

ABSTRACT The essential role of T cells in the resolution of primary murineChlamydia trachomatis genital tract infection is inarguable; however, much less is known about the mechanisms that confer resistance to reinfection. We previously established that CD4+ T cells and B cells contribute importantly to resistance to reinfection. In our current studies, we demonstrate that immune mice concurrently depleted of both CD4+ T cells and CD8+ T cells resisted reinfection as well as immunocompetent wild-type mice. The in vivo depletion of CD4+ and CD8+ T cells resulted in diminished chlamydia-specific delayed-type hypersensitivity responses, but antichlamydial antibody responses were unaffected. Our data indicate that immunity to chlamydial genital tract reinfection does not rely solely upon immune CD4+ or CD8+ T cells and further substantiate a predominant role for additional effector immune responses, such as B cells, in resistance to chlamydial genital tract reinfection.

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

Plasminogen Activation In Vivo upon Intravenous Infusion of DDAVP

1992 ◽  
Vol 67 (01) ◽  
pp. 111-116 ◽  
Author(s):  
Marcel Levi ◽  
Jan Paul de Boer ◽  
Dorina Roem ◽  
Jan Wouter ten Cate ◽  
C Erik Hack
Keyword(s):  
Monoclonal Antibodies ◽  
Plasminogen Activator ◽  
Plasma Levels ◽  
Fold Increase ◽  
Fibrinolytic System ◽  
Plasminogen Activation ◽  
Plasminogen Activator Activity ◽  
Insight Into

SummaryInfusion of desamino-d-arginine vasopressin (DDAVP) results in an increase in plasma plasminogen activator activity. Whether this increase results in the generation of plasmin in vivo has never been established.A novel sensitive radioimmunoassay (RIA) for the measurement of the complex between plasmin and its main inhibitor α2 antiplasmin (PAP complex) was developed using monoclonal antibodies preferentially reacting with complexed and inactivated α2-antiplasmin and monoclonal antibodies against plasmin. The assay was validated in healthy volunteers and in patients with an activated fibrinolytic system.Infusion of DDAVP in a randomized placebo controlled crossover study resulted in all volunteers in a 6.6-fold increase in PAP complex, which was maximal between 15 and 30 min after the start of the infusion. Hereafter, plasma levels of PAP complex decreased with an apparent half-life of disappearance of about 120 min. Infusion of DDAVP did not induce generation of thrombin, as measured by plasma levels of prothrombin fragment F1+2 and thrombin-antithrombin III (TAT) complex.We conclude that the increase in plasminogen activator activity upon the infusion of DDAVP results in the in vivo generation of plasmin, in the absence of coagulation activation. Studying the DDAVP induced increase in PAP complex of patients with thromboembolic disease and a defective plasminogen activator response upon DDAVP may provide more insight into the role of the fibrinolytic system in the pathogenesis of thrombosis.

696 Brentuximab vedotin, a CD30-directed antibody-drug conjugate, selectively depletes activated Tregs in vitro and in vivo

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A738-A738
Author(s):  
Bryan Grogan ◽  
Reice James ◽  
Michelle Ulrich ◽  
Shyra Gardai ◽  
Ryan Heiser ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Efflux Pump ◽  
Apoptotic Cell ◽  
T Cell Subsets ◽  
Memory Cells ◽  
Antibody Drug Conjugate ◽  
Selective Depletion

BackgroundRegulatory T cells (Tregs) play an important role in maintaining immune homeostasis, preventing excessive inflammation in normal tissues. In cancer, Tregs hamper anti-tumor immunosurveillance and facilitate immune evasion. Selective targeting of intratumoral Tregs is a potentially promising treatment approach. Orthogonal evaluation of tumor-infiltrating lymphocytes (TILs) in solid tumors in mice and humans have identified CCR8, and several tumor necrosis family receptors (TNFRs), including TNFSFR8 (CD30), as receptors differentially upregulated on intratumoral Tregs compared to normal tissue Tregs and other intratumoral T cells, making these intriguing therapeutic targets.Brentuximab vedotin (BV) is approved for classical Hodgkin lymphoma (cHL) across multiple lines of therapy including frontline use in stage III/IV cHL in combination with doxorubicin, vinblastine, and dacarbazine. BV is also approved for certain CD30-expressing T-cell lymphomas. BV is comprised of a CD30-directed monoclonal antibody conjugated to the highly potent microtubule-disrupting agent monomethyl auristatin E (MMAE).The activity of BV in lymphomas is thought to primarily result from tumor directed intracellular MMAE release, leading to mitotic arrest and apoptotic cell death.The role CD30 plays in normal immune function is unclear, with both costimulatory and proapoptotic roles described. CD30 is transiently upregulated following activation of memory T cells and expression has been linked to highly activated/suppressive IRF4+ effector Tregs.MethodsHere we evaluated the activity of BV on CD30-expressing T cell subsets in vitro and in vivo.ResultsTreatment of enriched T cell subsets with clinically relevant concentrations of BV drove selective depletion of CD30-expressing Tregs > CD30-expressingCD4+ T memory cells, with minimal effects on CD30-expressing CD8+ T memory cells. In a humanized xeno-GVHD model, treatment with BV selectively depleted Tregs resulting in accelerated wasting and robust T cell expansion. The observed differential activity on Tregs is likely attributable to significant increases in CD30 expression and reduced efflux pump activity relative to other T cell subsets. Interestingly, blockade of CD25 signaling prevents CD30 expression on T cell subsets without impacting proliferation, suggesting a link between CD25, the high affinity IL-2 receptor, and CD30 expression.ConclusionsTogether, these data suggest that BV may have an immunomodulatory effect through selective depletion of highly suppressive CD30-expressing Tregs.AcknowledgementsThe authors would like to thank Michael Harrison, PharmD for their assistance in abstract preparation.Ethics ApprovalAnimals studies were approved by and conducted in accordance with Seattle Genetics Institutional Care and Use Committee protocol #SGE-024.

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.

scholarly journals H-2 restriction of virus-specific T-cell-mediated effector functions in vivo. II. Adoptive transfer of delayed-type hypersensitivity to murine lymphocytic choriomeningits virus is restriced by the K and D region of H-2.

1976 ◽  
Vol 144 (3) ◽  
pp. 776-787 ◽  
Author(s):  
R M Zinkernagel
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Gamma Globulin ◽  
Effector T Cells ◽  
Delayed Type Hypersensitivity ◽  
T Effector Cells ◽  
Immune Lymphocytes ◽  
D Region

In mice, primary footpad swelling after local infection with lymphocytic choriomeningitis virus (LCMV) and delayed-type hypersensitivity (DTH) adoptively transferred by LCMV immune lymphocytes are T-cell dependent. Nude mice do not develop primary footpad swelling, and T-cell depletion abrogates the capacity to transfer LCMV-specific DTH. Effector T cells involved in eliciting dose-dependent DTH are virus specific in that vaccinia virus-immune lymphocytes could not elicit DTH in LCMV-infected mice. The adoptive transfer of DTH is restricted to H-2K or H-2D compatible donor-recipient combinations. Distinct from the fowl-gamma-globulin DTH model, I-region compatibility is neither necessary nor alone sufficient. Whatever the mechanisms involved in this K- or D-region associated restriction in vivo, it most likely operates at the level of T-cell recognition of "altered self" coded in K or D. T cells associated with the I region (helper T cells and DTH-T cells to fowl-gamma-globulin) are specific for soluble, defined, and inert antigens. T cells associated with the K and D region (T cells cytotoxic in vitro and in vivo for acute LCMV-infected cells, DTH effector T cells, and anti-viral T cells) are specific for infectious, multiplying virus. The fact that T-cell specificity is differentially linked with the I region or with the K and D regions of H-2 may reflect the fundamental biological differences of these antigens. Although it cannot be excluded that separate functional subclasses of T-effector cells could have self-recognizers for different cell surface structures coded in I or K and D, it is more likely that the antigen parameters determine whether T cells are specific for "altered" I or "altered" K- or D-coded structures.

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