scholarly journals Predominant Role for Directly Transfected Dendritic Cells in Antigen Presentation to CD8+ T Cells after Gene Gun Immunization

1998 ◽  
Vol 188 (6) ◽  
pp. 1075-1082 ◽  
Author(s):  
Angel Porgador ◽  
Kari R. Irvine ◽  
Akiko Iwasaki ◽  
Brian H. Barber ◽  
Nicholas P. Restifo ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Antigen Presentation ◽  
Cd8 T Cells ◽  
Cytotoxic T Cell ◽  
Gene Gun ◽  
Cross Presentation

Cutaneous gene (DNA) bombardment results in substantial expression of the encoded antigen in the epidermal layer as well as detectable expression in dendritic cells (DC) in draining lymph nodes (LNs). Under these conditions, two possible modes of DC antigen presentation to naive CD8+ T cells might exist: (a) presentation directly by gene-transfected DC trafficking to local lymph nodes, and (b) cross-presentation by untransfected DC of antigen released from or associated with transfected epidermal cells. The relative contributions of these distinct modes of antigen presentation to priming for cytotoxic T cell (CTL) responses have not been clearly established. Here we show that LN cells directly expressing the DNA-encoded antigen are rare; 24 h after five abdominal skin bombardments, the number of these cells does not exceed 50–100 cells in an individual draining LN. However, over this same time period, the total number of CD11c+ DC increases more than twofold, by an average of 20,000–30,000 DC per major draining node. This augmentation is due to gold bombardment and is independent of the presence of plasmid DNA. Most antigen-bearing cells in the LNs draining the site of DNA delivery appear to be DC and can be depleted by antibodies to an intact surface protein encoded by cotransfected DNA. This finding of predominant antigen presentation by directly transfected cells is also consistent with data from studies on cotransfection with antigen and CD86-encoding DNA, showing that priming of anti-mutant influenza nucleoprotein CTLs with a single immunization is dependent upon coexpression of the DNAs encoding nucleoprotein and B7.2 in the same cells. These observations provide insight into the relative roles of direct gene expression and cross-presentation in CD8+ T cell priming using gene gun immunization, and indicate that augmentation of direct DC gene expression may enhance such priming.

Regulation of Tim-3 function by binding to phosphatidylserine

2021 ◽  
Vol 478 (22) ◽  
pp. 3999-4004
Author(s):  
Lawrence P. Kane
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Transmembrane Protein ◽  
Cytotoxic T Cells ◽  
Cross Presentation ◽  
First Time

Tim-3 is a transmembrane protein that is highly expressed on subsets of chronically stimulated CD4+ helper and CD8+ cytotoxic T cells, with more transient expression during acute activation and infection. Tim-3 is also constitutively expressed by multiple types of myeloid cells. Like other TIM family members, Tim-3 can bind to phosphatidylserine displayed by apoptotic cells, and this interaction has been shown to mediate uptake of such cells by dendritic cells and cross-presentation of antigens to CD8+ T cells. In contrast, how the recognition of PS by Tim-3 might regulate the function of Tim-3+ T cells is not known. In their recent paper, Lemmon and colleagues demonstrate for the first time that recognition of PS by Tim-3 leads to enhanced T cell activation.

scholarly journals Cytomegalovirus inhibition of extrinsic apoptosis determines fitness and resistance to cytotoxic CD8 T cells

2020 ◽  
Vol 117 (23) ◽  
pp. 12961-12968 ◽  
Author(s):  
M. Zeeshan Chaudhry ◽  
Rosaely Casalegno-Garduno ◽  
Katarzyna M. Sitnik ◽  
Bahram Kasmapour ◽  
Ann-Kathrin Pulm ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Death Receptor ◽  
Cd8 T Cell ◽  
Cytotoxic T Cell ◽  
Caspase 8 ◽  
Infected Cells

Viral immune evasion is currently understood to focus on deflecting CD8 T cell recognition of infected cells by disrupting antigen presentation pathways. We evaluated viral interference with the ultimate step in cytotoxic T cell function, the death of infected cells. The viral inhibitor of caspase-8 activation (vICA) conserved in human cytomegalovirus (HCMV) and murine CMV (MCMV) prevents the activation of caspase-8 and proapoptotic signaling. We demonstrate the key role of vICA from either virus, in deflecting antigen-specific CD8 T cell-killing of infected cells. vICA-deficient mutants, lacking either UL36 or M36, exhibit greater susceptibility to CD8 T cell control than mutants lacking the set of immunoevasins known to disrupt antigen presentation via MHC class I. This difference is evident during infection in the natural mouse host infected with MCMV, in settings where virus-specific CD8 T cells are adoptively transferred. Finally, we identify the molecular mechanism through which vICA acts, demonstrating the central contribution of caspase-8 signaling at a point of convergence of death receptor-induced apoptosis and perforin/granzyme-dependent cytotoxicity.

scholarly journals 612 Human CLEC9A antibodies deliver NY-ESO-1 antigen to CD141+ dendritic cells to activate naïve and memory NY-ESO-1-specific CD8+ T cells

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A648-A648
Author(s):  
Kelly-Anne Masterman ◽  
Oscar Haigh ◽  
Kirsteen Tullett ◽  
Ingrid Leal-Rojas ◽  
Carina Walpole ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Ethics Committee ◽  
Cross Presentation ◽  
Cell Responses ◽  
Melanoma Patients

BackgroundDendritic cells (DC) are crucial for the efficacy of cancer vaccines, but current vaccines do not harness the key cDC1 subtype required for effective CD8+ T cell mediated tumor immune responses. Vaccine immunogenicity could be enhanced by specific delivery of immunogenic tumor antigens to CD141+ DC, the human cDC1 equivalent. CD141+ DC exclusively express the C-type-lectin-like receptor CLEC9A, which is important for the regulation of CD8+ T cell responses. This study developed a new vaccine that harnesses a human anti-CLEC9A antibody to specifically deliver the immunogenic tumor antigen, NY-ESO-1 to human CD141+ DC. The ability of the CLEC9A-NY-ESO-1 antibody to activate NY-ESO-1 specific naïve and memory CD8+ T cells was examined and compared to a vaccine comprised of a human DEC-205-NY-ESO-1 antibody that targets all human DC.MethodsHuman anti-CLEC9A, anti-DEC-205 and isotype control IgG4 antibodies were genetically fused to NY-ESO-1 polypeptide. Cross-presentation to NY-ESO-1- epitope specific CD8+ T cells and reactivity of T cell responses in melanoma patients was assessed by IFNγ production following incubation of CD141+ DC and patient peripheral blood mononuclear cells with targeting antibodies. Humanized mice containing human DC subsets and a repertoire of naïve NY-ESO-1-specific CD8+ T cells were used to investigate naïve T cell priming. T cell effector function was measured by expression of IFNγ, MIP-1β, TNF and CD107a and by lysis of target tumor cells.ResultsCLEC9A-NY-ESO-1 Ab were effective at mediating delivery and cross-presentation of multiple NY-ESO-1 epitopes by CD141+ DC for activation of NY-ESO-1-specific CD8+ T cells. When benchmarked to NY-ESO-1 conjugated to an untargeted control antibody or to anti-human DEC-205, CLEC9A-NY-ESO-1 was superior at ex vivo reactivation of NY-ESO-1-specific T cell responses in melanoma patients. Moreover, CLEC9A-NY-ESO-1 induced priming of naïve NY-ESO-1-specific CD8+ T cells with polyclonal effector function and potent tumor killing capacity in vitro.ConclusionsThese data advocate human CLEC9A-NY-ESO-1 antibody as an attractive strategy for specific targeting of CD141+ DC to enhance tumour immunogenicity in NY-ESO-1-expressing malignancies.Ethics ApprovalWritten informed consent was obtained for human sample acquisition in line with standards established by the Declaration of Helsinki. Study approval was granted by the Mater Human Research Ethics Committee (HREC13/MHS/83 and HREC13/MHS/86) and The U.S. Army Medical Research and Materiel Command (USAMRMC) Office of Research Protections, Human Research Protection Office (HRPO; A-18738.1, A-18738.2, A-18738.3). All animal experiments were approved by the University of Queensland Animal Ethics Committee and conducted in accordance with the Australian Code for the Care and Use of Animals for Scientific Purposes in addition to the laws of the United States and regulations of the Department of Agriculture.

Human CD1c+ dendritic cells secrete high levels of IL-12 and potently prime cytotoxic T-cell responses

Blood ◽  
2013 ◽  
Vol 122 (6) ◽  
pp. 932-942 ◽  
Author(s):  
Giulia Nizzoli ◽  
Jana Krietsch ◽  
Anja Weick ◽  
Svenja Steinfelder ◽  
Federica Facciotti ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cytotoxic T Cell ◽  
Cell Responses ◽  
Key Points ◽  
Cytotoxic Molecules ◽  
Cytotoxic T Cell Responses ◽  
Antigen Presenting

Key Points CD1c+ DC but not BDCA-3+ DC or other antigen-presenting cells secrete high amounts of bioactive IL-12. CD1c+ DC efficiently cross-present antigens, prime CD8+ T cells, and induce the highest levels of cytotoxic molecules.

scholarly journals Cross-priming CD8+ T cells by targeting antigens to human dendritic cells through DCIR

Blood ◽  
2010 ◽  
Vol 116 (10) ◽  
pp. 1685-1697 ◽  
Author(s):  
Eynav Klechevsky ◽  
Anne-Laure Flamar ◽  
Yanying Cao ◽  
Jean-Philippe Blanck ◽  
Maochang Liu ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Immunity ◽  
Cross Presentation ◽  
Cell Responses ◽  
Cell Immunity

Abstract We evaluated human CD8+ T-cell responses generated by targeting antigens to dendritic cells (DCs) through various lectin receptors. We found the immunoreceptor tyrosine-based inhibitory motif-containing DC immunoreceptor (DCIR) to mediate potent cross-presentation. A single exposure to a low dose of anti-DCIR–antigen conjugate initiated antigen-specific CD8+ T-cell immunity by all human DC subsets including ex vivo–generated DCs, skin-isolated Langerhans cells, and blood myeloid DCs and plasmacytoid DCs. The delivery of influenza matrix protein (FluMP) through DCIR resulted in expansion of FluMP-specific memory CD8+ T cells. Enhanced specific CD8+ T-cell responses were observed when an antigen was delivered to the DCs via DCIR, compared with those induced by a free antigen, or antigen conjugated to a control monoclonal antibody or delivered via DC-SIGN, another lectin receptor. DCIR targeting also induced primary CD8+ T-cell responses against self (MART-1) and viral (HIV gag) antigens. Addition of Toll-like receptor (TLR) 7/8 agonist enhanced DCIR-mediated cross-presentation as well as cross-priming, particularly when combined with a CD40 signal. TLR7/8 activation was associated with increased expansion of the primed CD8+ T cells, high production of interferon-γ and tumor necrosis factor-α, and reduced levels of type 2–associated cytokines. Thus, antigen targeting via the human DCIR receptor allows activation of specific CD8+ T-cell immunity.

CD8+ T-cell–mediated killing of donor dendritic cells prevents alloreactive T helper type-2 responses in vivo

Blood ◽  
2006 ◽  
Vol 108 (7) ◽  
pp. 2257-2264 ◽  
Author(s):  
Sophie Laffont ◽  
Jérôme D. Coudert ◽  
Lucile Garidou ◽  
Laurent Delpy ◽  
Aurélie Wiedemann ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Cd4 T Cell ◽  
Th2 Cell ◽  
Draining Lymph Nodes

Abstract Accumulating evidence indicates that, in absence of CD8+ T-cell activation, CD4+ T-cell–mediated allograft rejection is associated with a dominant Th2-cell response and eosinophil infiltrates. In this study, we analyzed the mechanisms by which CD8+ T cells regulate alloreactive CD4+ T-cell priming and differentiation into interleukin 4 (IL-4)–producing cells. We showed that interferon γ (IFN-γ) production by CD8+ T cells was dispensable for the inhibition of Th2-cell development, as well as tissue eosinophilia and type 2 cytokine production in the rejected grafts. Since we noticed that CD8+ T cells not only suppressed Th2 differentiation, but also down-modulated the overall priming of alloreactive CD4+ T cells, we evaluated whether CD8+ T cells act by limiting the accumulation of donor-derived dendritic cells (DCs) in lymph nodes. We found that indeed, alloreactive CD8+ T cells rapidly eliminated allogeneic DCs from T-cell areas of draining lymph nodes, through a perforin-dependent mechanism. Thus, our data demonstrate that cytotoxic T lymphocyte (CTL)–mediated clearance of allogeneic DCs is a negative feedback mechanism that limits the duration of alloantigen presentation in draining lymph nodes, thereby modulating the amplitude and polarization of the primary alloreactive CD4+ T-cell responses.

scholarly journals Cross-presentation of a TAP-independent signal peptide induces CD8 T immunity to escaped cancers but necessitates anchor replacement

2021 ◽  
Author(s):  
Koen A. Marijt ◽  
Lisa Griffioen ◽  
Laura Blijleven ◽  
Sjoerd. H. van der Burg ◽  
Thorbald van Hall
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cancer Cells ◽  
Cd8 T Cells ◽  
Antigen Processing ◽  
Signal Sequence ◽  
Cell Repertoire ◽  
Cross Presentation ◽  
Normal Tissues ◽  
Cell Immunity

AbstractCancer cells frequently display defects in their antigen-processing pathway and thereby evade CD8 T cell immunity. We described a novel category of cancer antigens, named TEIPP, that emerge on cancers with functional loss of the peptide pump TAP. TEIPPs are non-mutated neoantigens despite their ‘self’ origin by virtue of their absence on normal tissues. Here, we describe the development of a synthetic long peptide (SLP) vaccine for the most immunogenic TEIPP antigen identified thus far, derived from the TAP-independent LRPAP1 signal sequence. LRPAP121–30-specific CD8 T cells were present in blood of all tested healthy donors as well as patients with non-small cell lung adenocarcinoma. SLPs with natural flanking, however, failed to be cross-presented by monocyte-derived dendritic cells. Since the C-terminus of LRPAP121–30 is an unconventional and weakly binding serine (S), we investigated if replacement of this anchor would result in efficient cross-presentation. Exchange into a valine (V) resulted in higher HLA-A2 binding affinity and enhanced T cell stimulation. Importantly, CD8 T cells isolated using the V-variant were able to bind tetramers with the natural S-variant and respond to TAP-deficient cancer cells. A functional screen with an array of N-terminal and C-terminal extended SLPs pointed at the 24-mer V-SLP, elongated at the N-terminus, as most optimal vaccine candidate. This SLP was efficiently cross-presented and consistently induced a strong polyclonal LRPAP121–30-specific CD8 T cells from the endogenous T cell repertoire. Thus, we designed a TEIPP SLP vaccine from the LRPAP1 signal sequence ready for validation in clinical trials.

scholarly journals Methotrexate enhances antigen presentation and maturation of tumour antigen-loaded dendritic cells through NLRP3 inflammasome activation: a strategy for dendritic cell-based cancer vaccine

2021 ◽  
Vol 13 ◽  
pp. 175883592098705
Author(s):  
Gao-Na Shi ◽  
Min Hu ◽  
Chengjuan Chen ◽  
Junmin Fu ◽  
Shuai Shao ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
Nlrp3 Inflammasome ◽  
Tumour Antigen ◽  
Inflammasome Activation ◽  
Antigen Uptake ◽  
Nlrp3 Inflammasome Activation ◽  
Dc Maturation

Background: Dendritic cells (DCs) are antigen-presenting cells that play a pivotal role in adaptive cell-mediated immunity by priming and activating T cells against specific tumour and pathogenic antigens. Methotrexate (MTX), a folate derivative, functions as an immunoregulatory agent. However, the possible effect of MTX on tumour antigen-loaded DCs has not yet been investigated. Methods: We analysed the effect of MTX on the maturation and function of DCs along with tumour cell lysates (TCLs). Using bone marrow-derived DCs, we investigated the effect of MTX combined TCL-loaded DCs on T cells priming and proliferation. We also tested the anti-tumour immune effect on DCs when treated with MTX and/or TCL in vivo. Results: MTX combined with TCL not only enhanced DC maturation and stimulated cytokine release but also promoted CD8+ T cell activation and proliferation. The latter was associated with increased tumour antigen uptake and cross-presentation to T cells. Mechanistically, DC maturation and antigen presentation were partly modulated by NLRP3 inflammasome activation. Furthermore, immunisation of mice with MTX and TCL-pulsed DCs before a tumour challenge significantly delayed tumour onset and retarded its growth. This protective effect was due to priming of IFN-γ releasing CD8+ T cells and enhanced killing of tumour cells by cytotoxic T lymphocytes isolated from these immunised mice. Conclusion: MTX can function as a potent adjuvant in DC vaccines by increasing antigen presentation and T cell priming. Our findings provide a new strategy for the application of DC-based anti-tumour immunotherapy.

scholarly journals Characterization of human cytomegalovirus peptide–specific CD8+ T-cell repertoire diversity following in vitro restimulation by antigen-pulsed dendritic cells

Blood ◽  
2002 ◽  
Vol 99 (1) ◽  
pp. 213-223 ◽  
Author(s):  
Karl Peggs ◽  
Stephanie Verfuerth ◽  
Arnold Pizzey ◽  
Jenni Ainsworth ◽  
Paul Moss ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Viral Replication ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
T Cell Repertoire ◽  
Cell Repertoire ◽  
Repertoire Diversity ◽  
Clonal Composition

Under conditions of impaired T-cell immunity, human cytomegalovirus (HCMV) can reactivate from lifelong latency, resulting in potentially fatal disease. A crucial role for CD8+ T cells has been demonstrated in control of viral replication, and high levels of HCMV-specific cytotoxic T-lymphocytes are seen in immunocompetent HCMV-seropositive individuals despite very low viral loads. Elucidation of the minimum portion of the anti-HCMV T-cell repertoire that is required to suppress viral replication requires further study of clonal composition. The ability of dendritic cells to take up and process exogenous viral antigen by constitutive macropinocytosis was used to study HCMV-specific T-cell memory in the absence of viral replication. The specificity and clonal composition of the CD8+ T-cell responses were evaluated using HLA tetrameric complexes and T-cell receptor β chain (TCRBV) spectratypic analyses. There was a skewed reactivity toward the matrix protein pp65, with up to 40-fold expansion of CD8+ T cells directed toward a single peptide-MHC combination. Individual expansions detected on TCRBV spectratype analysis were HCMV-specific and composed of single or highly restricted numbers of clones. There was preferential TCRBV gene usage (BV6.1/6.2, BV8, and BV13 in HLA-A*0201+ individuals) but lack of conservation of CDR3 length and junctional motifs between donors. While there was a spectrum of TCR repertoire diversity directed toward individual MHC-peptide combinations between donors, a relatively small number of clones appeared to predominate the response in each case. These data provide further insight into the range of anti-HCMV responses and will aid the design and monitoring of adoptive immunotherapy protocols.

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