scholarly journals Importance of integrin LFA-1 deactivation for the generation of immune responses

2005 ◽  
Vol 201 (12) ◽  
pp. 1987-1998 ◽  
Author(s):  
Monika Semmrich ◽  
Andrew Smith ◽  
Carolin Feterowski ◽  
Sandra Beer ◽  
Britta Engelhardt ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Activity ◽  
Intercellular Adhesion Molecule ◽  
Cytotoxic T Cell ◽  
Lymphocyte Function ◽  
Intercellular Adhesion Molecule 1

The dynamic regulation of ligand binding is considered crucial for integrin function. However, the importance of activity regulation for integrin function in vivo is largely unknown. Here, we have applied gene targeting to delete the GFFKR sequence of the lymphocyte function-associated antigen–1 (LFA-1) αL subunit cytoplasmic domain in mouse germline. Lymphocytes from Lfa-1d/d mutant mice showed constitutive activation of LFA-1–mediated cell adhesion and impaired de-adhesion from intercellular adhesion molecule-1 that resulted in defective cell migration. In contrast, signaling through LFA-1 was not affected in Lfa-1d/d cells. T cell activation by superantigen-loaded and allogeneic APCs, cytotoxic T cell activity, T-dependent humoral immune responses, and neutrophil recruitment during aseptic peritonitis were impaired in Lfa-1d/d mice. Thus, deactivation of LFA-1 and disassembly of LFA-1–mediated cell contacts seem to be vital for the generation of normal immune responses.

scholarly journals ICAM-1 depletion in the center of immunological synapses is important for calcium releasing in T-cells

2018 ◽  
Vol 11 (02) ◽  
pp. 1750015 ◽  
Author(s):  
Yuanzhen Suo ◽  
Wei Lin ◽  
Yuting Deng ◽  
Zhichao Fan ◽  
Lizeng Qin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Calcium Signaling ◽  
T Cell Activation ◽  
Cell Activation ◽  
Calcium Release ◽  
Immunological Synapse ◽  
Intercellular Adhesion Molecule ◽  
Lymphocyte Function ◽  
Intercellular Adhesion Molecule 1

T-cell activation requires the formation of the immunological synapse (IS) between a T-cell and an antigen-presenting cell (APC) to control the development of the adaptive immune response. However, calcium release, an initial signal of T-cell activation, has been found to occur before IS formation. The mechanism for triggering the calcium signaling and relationship between calcium release and IS formation remains unclear. Herein, using live-cell imaging, we found that intercellular adhesion molecule 1 (ICAM-1), an essential molecule for IS formation, accumulated and then was depleted at the center of the synapse before complete IS formation. During the process of ICAM-1 depletion, calcium was released. If ICAM-1 failed to be depleted from the center of the synapse, the sustained calcium signaling could not be induced. Moreover, depletion of ICAM-1 in ISs preferentially occurred with the contact of antigen-specific T-cells and dendritic cells (DCs). Blocking the binding of ICAM-1 and lymphocyte function-associated antigen 1 (LFA-1), ICAM-1 failed to deplete at the center of the synapse, and calcium release in T-cells decreased. In studying the mechanism of how the depletion of ICAM-1 could influence calcium release in T-cells, we found that the movement of ICAM-1 was associated with the localization of LFA-1 in the IS, which affected the localization of calcium microdomains, ORAI1 and mitochondria in IS. Therefore, the depletion of ICAM-1 in the center of the synapse is an important factor for an initial sustained calcium release in T-cells.

Experimental silicosis: a shift to a preferential IFN-γ-based Th1 response in thoracic lymph nodes

2000 ◽  
Vol 278 (6) ◽  
pp. L1221-L1230 ◽  
Author(s):  
Holger Garn ◽  
Anke Friedetzky ◽  
Andrea Kirchner ◽  
Ruth Jäger ◽  
Diethard Gemsa
Keyword(s):  
T Cell ◽  
Lymph Nodes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cytotoxic T Cell ◽  
Mrna Levels ◽  
Ifn Γ

In chronic silicosis, mechanisms leading to lymphocyte activation are still poorly understood, although it is well known that not only the lung but also the draining lymph nodes are affected. In the present study, we investigated T-cell activation by analysis of cytokine expression in the enlarged thoracic lymph nodes of rats 2 mo after an 8-day silica aerosol exposure. In the case of helper T cell (Th) type 1 cytokines, we found a significant increase in interferon (IFN)-γ mRNA expression, whereas interleukin (IL)-2 expression remained unchanged. In contrast, gene transcription for the Th2-type cytokines IL-4 and IL-10 was diminished. In addition, with use of an in vitro lymphocyte-macrophage coculture system, an enhanced IFN-γ and a reduced IL-10 release were shown with cells from silicotic animals. With regard to IFN-γ-inducing cytokines, we observed enhanced IL-12 mRNA levels in vivo, whereas IL-18 gene expression was slightly decreased. These data indicate that a persistent shift toward an IFN-γ-dominated type 1 (Th1/cytotoxic T cell type 1) T-cell reaction pattern occurred within the thoracic lymph nodes of silicotic animals. Thus a mutual activation of lymphocytes and macrophages may maintain the chronic inflammatory changes that characterize silicosis.

Activation of Peripheral Blood T Cells by Interaction and Migration Through Endothelium: Role of Lymphocyte Function Antigen-1/Intercellular Adhesion Molecule-1 and Interleukin-15

Blood ◽  
1999 ◽  
Vol 93 (3) ◽  
pp. 886-896 ◽  
Author(s):  
David Sancho ◽  
Marı́a Yáñez-Mó ◽  
Reyes Tejedor ◽  
Francisco Sánchez-Madrid
Keyword(s):  
T Cells ◽  
Cell Adhesion ◽  
T Cell ◽  
T Cell Activation ◽  
Adhesion Molecule ◽  
Cell Activation ◽  
Cell Subset ◽  
Intercellular Adhesion Molecule ◽  
Lymphocyte Function ◽  
Ifn Γ

Abstract Cell adhesion molecules have a key role in the migration of T cells to inflammatory foci. However, the effect of the endothelial-lymphocyte interaction on the activation of the latter cells remains unresolved. We have studied the effect of resting and stimulated endothelial cells (ECs) on the activation of peripheral blood T cells (PBTLs), as assessed by the expression of CD69 and CD25 activation antigens. The incubation of PBTLs with tumor necrosis factor-–activated EC monolayers, either alive or fixed, induced the expression of CD69 but not CD25, preferentially in the CD8+CD45RO+ cell subset. Furthermore, it induced the production of cytokines such as IFN-γ, but not that of interleukin-2 (IL-2) and IL-4. EC treated with other stimuli such as IL-1β, IFN-γ, or lipopolysaccharide also showed the same proactivatory effect on T cells. Lymphocyte activation was almost completely inhibited by blocking anti-CD18 and anti–intercellular adhesion molecule-1 (anti–ICAM-1) monoclonal antibodies (MoAbs), but only slightly affected by MoAbs against CD49d, vascular cell adhesion molecule-1, and anti–IL-15. In addition, the interaction of PBTL with immobilized ICAM-1 induced CD69 expression in the same memory T-cell subset. IL-15 induced T-cell activation with expression of CD69 and CD25, and production of IFN-γ, and its effect was additive with that triggered by cell adhesion to either EC or immobilized ICAM-1. The transmigration of PBTLs through either confluent EC monolayers or ICAM-1–coated membranes also induced efficiently the expression of CD69. When IL-15 was used as chemoattractant in these assays, a further enhancement in CD69 expression was observed in migrated cells. Together these results indicate that stimulated endothelium may have an important role in T-cell activation, through the lymphocyte function antigen-1/ICAM-1 pathway, and that IL-15 efficiently cooperates in this phenomenon. These observations could account for the abundance of CD69+ cells in the lymphocytic infiltrates of several chronic inflammatory diseases.

scholarly journals Cd2 Sets Quantitative Thresholds in T Cell Activation

1999 ◽  
Vol 190 (10) ◽  
pp. 1383-1392 ◽  
Author(s):  
Martin F. Bachmann ◽  
Marijke Barner ◽  
Manfred Kopf
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Dose Response ◽  
Response Curve ◽  
Cell Activation ◽  
Dose Response Curve ◽  
Lymphocyte Function

It has been proposed that CD2, which is highly expressed on T cells, serves to enhance T cell–antigen presenting cell (APC) adhesion and costimulate T cell activation. Here we analyzed the role of CD2 using CD2-deficient mice crossed with transgenic mice expressing a T cell receptor specific for lymphocytic choriomeningitis virus (LCMV)-derived peptide p33. We found that absence of CD2 on T cells shifted the p33-specific dose–response curve in vitro by a factor of 3–10. In comparison, stimulation of T cells in the absence of lymphocyte function–associated antigen (LFA)-1–intercellular adhesion molecule (ICAM)-1 interaction shifted the dose–response curve by a factor of 10, whereas absence of both CD2–CD48 and LFA-1–ICAM-1 interactions shifted the response by a factor of ∼100. This indicates that CD2 and LFA-1 facilitate T cell activation additively. T cell activation at low antigen density was blocked at its very first steps, as T cell APC conjugate formation, TCR triggering, and Ca2+ fluxes were affected by the absence of CD2. In vivo, LCMV-specific, CD2-deficient T cells proliferated normally upon infection with live virus but responded in a reduced fashion upon cross-priming. Thus, CD2 sets quantitative thresholds and fine-tunes T cell activation both in vitro and in vivo.

Activation of Peripheral Blood T Cells by Interaction and Migration Through Endothelium: Role of Lymphocyte Function Antigen-1/Intercellular Adhesion Molecule-1 and Interleukin-15

Blood ◽  
1999 ◽  
Vol 93 (3) ◽  
pp. 886-896 ◽  
Author(s):  
David Sancho ◽  
Marı́a Yáñez-Mó ◽  
Reyes Tejedor ◽  
Francisco Sánchez-Madrid
Keyword(s):  
T Cells ◽  
Cell Adhesion ◽  
T Cell ◽  
T Cell Activation ◽  
Adhesion Molecule ◽  
Cell Activation ◽  
Cell Subset ◽  
Intercellular Adhesion Molecule ◽  
Lymphocyte Function ◽  
Ifn Γ

Cell adhesion molecules have a key role in the migration of T cells to inflammatory foci. However, the effect of the endothelial-lymphocyte interaction on the activation of the latter cells remains unresolved. We have studied the effect of resting and stimulated endothelial cells (ECs) on the activation of peripheral blood T cells (PBTLs), as assessed by the expression of CD69 and CD25 activation antigens. The incubation of PBTLs with tumor necrosis factor-–activated EC monolayers, either alive or fixed, induced the expression of CD69 but not CD25, preferentially in the CD8+CD45RO+ cell subset. Furthermore, it induced the production of cytokines such as IFN-γ, but not that of interleukin-2 (IL-2) and IL-4. EC treated with other stimuli such as IL-1β, IFN-γ, or lipopolysaccharide also showed the same proactivatory effect on T cells. Lymphocyte activation was almost completely inhibited by blocking anti-CD18 and anti–intercellular adhesion molecule-1 (anti–ICAM-1) monoclonal antibodies (MoAbs), but only slightly affected by MoAbs against CD49d, vascular cell adhesion molecule-1, and anti–IL-15. In addition, the interaction of PBTL with immobilized ICAM-1 induced CD69 expression in the same memory T-cell subset. IL-15 induced T-cell activation with expression of CD69 and CD25, and production of IFN-γ, and its effect was additive with that triggered by cell adhesion to either EC or immobilized ICAM-1. The transmigration of PBTLs through either confluent EC monolayers or ICAM-1–coated membranes also induced efficiently the expression of CD69. When IL-15 was used as chemoattractant in these assays, a further enhancement in CD69 expression was observed in migrated cells. Together these results indicate that stimulated endothelium may have an important role in T-cell activation, through the lymphocyte function antigen-1/ICAM-1 pathway, and that IL-15 efficiently cooperates in this phenomenon. These observations could account for the abundance of CD69+ cells in the lymphocytic infiltrates of several chronic inflammatory diseases.

550 An Axl-targeting monoclonal antibody that inhibits Axl activity and potently stimulates the innate immune response

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A587-A587
Author(s):  
Diego Alvarado ◽  
Laura Vitale ◽  
Mike Murphy ◽  
Thomas O’Neill ◽  
Edward Natoli ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
T Cell ◽  
Tumor Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Human Cancer ◽  
Cell Activity ◽  
Negative Regulator

BackgroundAxl is a member of the TAM (Tyro3/Axl/MerTK) family of receptor tyrosine kinases and a negative regulator of innate immunity. Activation of Axl through its ligand Gas6 leads to suppression of myeloid cell activity, while its activation in tumor cells drives tumor growth, metastasis, and is associated with acquired resistance to targeted therapies, radiotherapy and chemotherapy.MethodsPurified monoclonal antibodies and variants thereof were tested in human cancer lines and primary human myeloid cells for effects on Axl signaling and immune activation, respectively.ResultsWe describe a humanized IgG1 Axl-targeting monoclonal antibody (mAb), CDX-0168, that binds to the ligand-binding domain of Axl with sub-nanomolar affinity and potently inhibits Gas6 binding. In tumor cells, CDX-0168 inhibits Gas6-dependent Axl phosphorylation and signaling and elicits tumor cell killing via ADCC in vitro and in vivo. In primary human immune cells, CDX-0168 treatment induces potent release of pro-inflammatory cytokines and chemokines from dendritic cells, monocytes and macrophages through an Fc receptor-dependent mechanism and enhanced T cell activation in mixed lymphocyte reactions. Axl inhibition may further enhance antitumor activity associated with PD-(L)1 blockade. To this end, we generated a tetravalent bispecific Axl x PD-L1 antibody combining CDX-0168 with a potent anti-PD-L1 mAb (9H9) using an IgG-scFv format. The bispecific antibody elicits greater cytokine release and T cell activation in vitro than the combination of the parental antibodies, while maintaining robust Axl and PD-L1 blockade.ConclusionsAdditional studies investigating simultaneous blockade of the Axl and PD-L1 pathways with other agents may further exploit the potential for this novel anti-cancer therapeutic approach.

scholarly journals Enhanced Dendritic Cell Maturation by TNF-α or Cytidine-Phosphate-Guanosine DNA Drives T Cell Activation In Vitro and Therapeutic Anti-Tumor Immune Responses In Vivo

2000 ◽  
Vol 165 (11) ◽  
pp. 6278-6286 ◽  
Author(s):  
Christoph Brunner ◽  
Julia Seiderer ◽  
Angelika Schlamp ◽  
Martin Bidlingmaier ◽  
Andreas Eigler ◽  
...  
Keyword(s):  
T Cell ◽  
Dendritic Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Dendritic Cell Maturation ◽  
Cell Maturation ◽  
Tnf Α

scholarly journals Development of Acute Myeloid Leukemia Cell Membrane Coated Nanoparticles (AMCNPs) for Cancer Vaccination Immunotherapy

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4062-4062
Author(s):  
Daniel T Johnson ◽  
Ashley V Kroll ◽  
Ronnie H Fang ◽  
Justin Kline ◽  
Liangfang Zhang ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Membrane ◽  
Immune Responses ◽  
Mhc Class I ◽  
T Cell Activation ◽  
Cell Activation ◽  
Residual Disease ◽  
Surface Antigens ◽  
Class I

Abstract Acute Myeloid Leukemia (AML) is the most common acute leukemia in adults and has a five-year survival rate under 50%. Most patients will relapse even after complete remission is achieved through standard chemotherapy. Thus, one barrier in current AML therapy is how to target the minimal residual disease during remission. Recent developments in understanding cancer cell antigen presentation and immunosuppression have revealed the promise of cancer immunotherapy in activating immune responses to target residual disease. Each leukemia patient has a unique spectrum of cell surface antigens, which are mostly uncharacterized. If these antigens can be efficiently presented to the patient's immune system, immune responses to fight the leukemia can be significantly enhanced. We therefore sought to develop and characterize an AML cell membrane-coated nanoparticle (AMCNP) platform with nanoparticles (NPs) carrying the same surface antigens as the source leukemic cells for use as an anti-cancer vaccine. To demonstrate that our AMCNP vaccines enhance leukemia-specific antigen dendritic cell (DC) presentation and T-cell responses, we modified the C1498 murine AML cell line to express membrane-bound chicken ovalbumin (C1498-mOVA) as a model antigen. We confirmed that the C1498-mOVA line presents the OVA MHC class-I "SIINFEKL" antigen through flow-cytometry and LacZ B3Z T-cell activation assays. The C1498-mOVA line remained leukemogenic when injected into C57BL/6 mice, with survival times between 30 and 55 days. We generated both C1498 and C1498-mOVA membrane-coated nanoparticles, that were packaged with CpG oligo-deoxynucleotides (CpG) as an immune-stimulatory adjuvant. The final AMCNPs exhibit a core-shell structure with uniform coating as shown by transmission electron microscopy. The C1498-mOVA AMCNPs retained mOVA antigen. To confirm that the C1498-mOVA AMCNPs can effectively stimulate DC OVA MHC class I cross-presentation, we pulsed primary bone marrow derived DCs with C1498 AMCNPs or C1498-mOVA AMCNPs; only the C1498-mOVA AMCNP pulsed DCs specifically elicited OVA MHC class-I T-cell activation in lacZ B3Z T-cell activation assays. To verify that the AMCNPs can elicit antigen-specific immune responses in vivo, we vaccinated C57BL/6 mice with C1498 AMCNPs, C1498-mOVA AMCNPs, or equivalent amounts of whole cell lysates. When stimulated ex vivo with OVA peptide, immune-cell preparations from the C1498-mOVA AMCNP vaccinated mice showed significantly enhanced production of OVA-specific T-cells and IFN-γ, demonstrating increased immune responses. To assess if the enhanced cellular immunity afforded by the C1498-mOVA AMCNP formula can translate into functional rejection of leukemia cells, we performed a prophylactic study using the C1498-mOVA model. Mice vaccinated with the C1498-mOVA AMCNPs all survived beyond 120 days post C1498-mOVA cell challenge, compared to mock treated control mice which had a median survival of 60 days. Collectively, we developed an AMCNP platform that carries AML surface antigens and can be packaged with immunostimulatory adjuvants. These AMCNPs retained AML specific antigens, elicited enhanced antigen specific immune responses after in vivo vaccination, and improved immunity against AML challenge. Therefore, using AML cell membrane coated NPs to enhance anticancer immunity is a feasible strategy for AML vaccination immunotherapy. Disclosures Kline: iTeos: Research Funding; Merck: Honoraria, Research Funding.

scholarly journals Functionalisation of Virus-Like Particles Enhances Antitumour Immune Responses

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Katrin Kramer ◽  
Farah Al-Barwani ◽  
Margaret A. Baird ◽  
Vivienne L. Young ◽  
David S. Larsen ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mannose Receptor ◽  
Virus Like Particles ◽  
Rabbit Haemorrhagic Disease

Virus-like particles (VLP) from the rabbit haemorrhagic disease virus (RHDV) can deliver tumour antigens to induce anticancer immune responses. In this study, we explored how RHDV VLP can be functionalised to enhance the immune response by increasing antigen loading, incorporating linkers to enhance epitope processing, and targeting receptor-mediated internalisation of VLP. RHDV VLP were developed to deliver up to three copies of gp10025–33 which contained proteasome cleavable linkers to target the correct processing of the epitope. Addition of mono- and dimannosides, conjugated to the surface of the gp100 VLP, would utilise a second pathway of internalisation, mannose receptor mediated, to further augment antigen internalised by phagocytosis/macropinocytosis. In vitro cell culture studies showed that a processing linker at the C-terminus of the epitope (gp100.1LC) induced enhanced T-cell activation (7.3 ng/ml interferon- (IFN-) γ release) compared to no linker (3.0 ng/ml IFN-γ) or the linker at the N-terminus (0.8 ng/ml IFN-γ). VLP delivering two (gp100.2L) or three (gp100.3L) gp100 epitopes induced similar high T-cell activation (7.6 ng/ml IFN-γ) compared to gp100.1LC. An in vivo cytotoxicity assay and a therapeutic tumour trial confirmed that mice vaccinated with either gp100.2L or gp100.3L induced a specific antitumour immune response. Mannosylation of the gp100.2L VLP further enhanced the generated immune response, demonstrated by prolonged survival of mice vaccinated with dimannosylated gp100.2L VLP (D-gp100.2L) by 22 days compared to gp100.2L-vaccinated mice. This study showed that functionalisation of RHDV VLP by addition of an epitope-processing linker and mannosylation of the surface facilitates the efficacy of VLP as vaccination vectors for tumour immunotherapy.

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