scholarly journals Central Tolerance to Tissue-specific Antigens Mediated by Direct and Indirect Antigen Presentation

2004 ◽  
Vol 200 (8) ◽  
pp. 1039-1049 ◽  
Author(s):  
Alena M. Gallegos ◽  
Michael J. Bevan
Keyword(s):  
T Cells ◽  
Antigen Presentation ◽  
Cd8 T Cells ◽  
Thymic Epithelial Cells ◽  
Clonal Deletion ◽  
Autoreactive T Cells ◽  
Tissue Specific ◽  
Central Tolerance ◽  
Cross Presentation ◽  
Specific Antigens

Intrathymic expression of tissue-specific antigens (TSAs) by medullary thymic epithelial cells (Mtecs) leads to deletion of autoreactive T cells. However, because Mtecs are known to be poor antigen-presenting cells (APCs) for tolerance to ubiquitous antigens, and very few Mtecs express a given TSA, it was unclear if central tolerance to TSA was induced directly by Mtec antigen presentation or indirectly by thymic bone marrow (BM)-derived cells via cross-presentation. We show that professional BM-derived APCs acquire TSAs from Mtecs and delete autoreactive CD8 and CD4 T cells. Although direct antigen presentation by Mtecs did not delete the CD4 T cell population tested in this study, Mtec presentation efficiently deleted both monoclonal and polyclonal populations of CD8 T cells. For developing CD8 T cells, deletion by BM-derived APC and by Mtec presentation occurred abruptly at the transitional, CD4high CD8low TCRintermediate stage, presumably as the cells transit from the cortex to the medulla. These studies reveal a cooperative relationship between Mtecs and BM-derived cells in thymic elimination of autoreactive T cells. Although Mtecs synthesize TSAs and delete a subset of autoreactive T cells, BM-derived cells extend the range of clonal deletion by cross-presenting antigen captured from Mtecs.

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.

scholarly journals Enhancement of an anti-tumor immune response by transient blockade of central T cell tolerance

2014 ◽  
Vol 211 (5) ◽  
pp. 761-768 ◽  
Author(s):  
Imran S. Khan ◽  
Maria L. Mouchess ◽  
Meng-Lei Zhu ◽  
Bridget Conley ◽  
Kayla J. Fasano ◽  
...  
Keyword(s):  
T Cells ◽  
Ectopic Expression ◽  
Therapeutic Benefit ◽  
Effector T Cells ◽  
Thymic Epithelial Cells ◽  
Central Tolerance ◽  
Specific Effector ◽  
Medullary Thymic Epithelial Cells ◽  
Specific Antigens

Thymic central tolerance is a critical process that prevents autoimmunity but also presents a challenge to the generation of anti-tumor immune responses. Medullary thymic epithelial cells (mTECs) eliminate self-reactive T cells by displaying a diverse repertoire of tissue-specific antigens (TSAs) that are also shared by tumors. Therefore, while protecting against autoimmunity, mTECs simultaneously limit the generation of tumor-specific effector T cells by expressing tumor self-antigens. This ectopic expression of TSAs largely depends on autoimmune regulator (Aire), which is expressed in mature mTECs. Thus, therapies to deplete Aire-expressing mTECs represent an attractive strategy to increase the pool of tumor-specific effector T cells. Recent work has implicated the TNF family members RANK and RANK-Ligand (RANKL) in the development of Aire-expressing mTECs. We show that in vivo RANKL blockade selectively and transiently depletes Aire and TSA expression in the thymus to create a window of defective negative selection. Furthermore, we demonstrate that RANKL blockade can rescue melanoma-specific T cells from thymic deletion and that persistence of these tumor-specific effector T cells promoted increased host survival in response to tumor challenge. These results indicate that modulating central tolerance through RANKL can alter thymic output and potentially provide therapeutic benefit by enhancing anti-tumor immunity.

scholarly journals Thymic B Cells as a New Player in the Type 1 Diabetes Response

2021 ◽  
Vol 12 ◽  
Author(s):  
Richard B. Greaves ◽  
Dawei Chen ◽  
E. Allison Green
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
B Cells ◽  
Small Population ◽  
Thymic Epithelial Cells ◽  
Lymphoid Tissues ◽  
Autoreactive T Cells ◽  
Central Tolerance ◽  
Autoimmune Conditions

Type 1 diabetes (T1d) results from a sustained autoreactive T and B cell response towards insulin-producing β cells in the islets of Langerhans. The autoreactive nature of the condition has led to many investigations addressing the genetic or cellular changes in primary lymphoid tissues that impairs central tolerance- a key process in the deletion of autoreactive T and B cells during their development. For T cells, these studies have largely focused on medullary thymic epithelial cells (mTECs) critical for the effective negative selection of autoreactive T cells in the thymus. Recently, a new cellular player that impacts positively or negatively on the deletion of autoreactive T cells during their development has come to light, thymic B cells. Normally a small population within the thymus of mouse and man, thymic B cells expand in T1d as well as other autoimmune conditions, reside in thymic ectopic germinal centres and secrete autoantibodies that bind selective mTECs precipitating mTEC death. In this review we will discuss the ontogeny, characteristics and functionality of thymic B cells in healthy and autoimmune settings. Furthermore, we explore how in silico approaches may help decipher the complex cellular interplay of thymic B cells with other cells within the thymic microenvironment leading to new avenues for therapeutic intervention.

Characterization of HLA-A*0201 restricted cytotoxic CD8+ T cells directed against ewing tumor specific antigens

2009 ◽  
Vol 221 (03) ◽  
Author(s):  
S Pirson ◽  
U Thiel ◽  
H Bernhard ◽  
GHS Richter ◽  
S Burdach
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Specific Antigens ◽  
Ewing Tumor

Antigen cross-presentation in the liver generates protective memory CD8+ T cells in the absence of inflammation

2012 ◽  
Vol 50 (01) ◽  
Author(s):  
JP Böttcher ◽  
D Stabenow ◽  
S Debey-Pascher ◽  
A Staratschek-Jox ◽  
J Grell ◽  
...  
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Memory Cd8 T Cells ◽  
Cross Presentation

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 EXTH-43. GENERATION OF A B-CELL-BASED VACCINE FOR THE TREATMENT OF GLIOBLASTOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii96-ii96
Author(s):  
Catalina Lee Chang ◽  
Jason Miska ◽  
David Hou ◽  
Aida Rashidi ◽  
Peng Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
B Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Cross Presentation ◽  
Control Tumor Growth ◽  
Efficient Alternative ◽  
Control Tumor ◽  
Secondary Lymphoid Organs

Abstract Immunotherapy has revolutionized the treatment of many tumors. However, most glioblastoma (GBM) patients have not, so far, benefited from such successes. With the goal of exploring ways to boost anti-GBM immunity, we developed a B-cell-based vaccine (BVax) that consists of 4-1BBL+ B cells activated with CD40 agonism and IFNg stimulation. BVaxmigrate to key secondary lymphoid organs and are proficient at antigen cross-presentation, which promotes both the survival and functionality of CD8+ T cells. A combination of radiation, BVax, and PD-L1 blockade conferred tumor eradication in 80% of treated tumor-bearing animals. This treatment elicited immunologic memory that prevented the growth of new tumors upon subsequent re-injection in cured mice. GBM patient-derived BVax were successful in activating autologous CD8+ T cells; these T cells showed a strong ability to kill autologous glioma cells. In addition to the role in activating CD8+ T cells, BVax produce tumor-specific antibodies able to control tumor growth via antibody-mediated cell cytotoxicity. In conclusion, BVax tackles GBM immunosurveillance escape by using both cellular (CD8+ T-cell activation) and humoral (anti-tumor antibody production) immunity. Our study provides an efficient alternative to current immunotherapeutic approaches that can be readily translated to the clinic.

scholarly journals Endogenous antigen presentation impacts on T-box transcription factor expression and functional maturation of CD8+ T cells

Blood ◽  
2012 ◽  
Vol 120 (16) ◽  
pp. 3237-3245 ◽  
Author(s):  
Corey Smith ◽  
Diah Elhassen ◽  
Stephanie Gras ◽  
Katherine K. Wynn ◽  
Vijayendra Dasari ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factors ◽  
Antigen Presentation ◽  
Cd8 T Cells ◽  
Viral Antigen ◽  
Cytotoxic T Lymphocyte ◽  
Granzyme B ◽  
T Box ◽  
Differentiation Status ◽  
Human Cmv

Abstract T-box transcription factors T-bet (Tbx21) and Eomesodermin (Eomes) are critical players in CD8+ cytotoxic T lymphocyte effector function and differentiation, but how the expression of these transcription factors is regulated remains poorly defined. Here we show that dominant T cells directed toward human CMV, expressing significantly higher levels of T-bet with graded loss of Eomes expression (T-bethiEomeshi/lo), are more efficient in recognizing endogenously processed peptide-major histocompatibility complexes (pMHC) compared with subdominant virus-specific T cells expressing lower levels of T-bet and high levels of Eomes (T-betintEomeshi). Paradoxically, the T-bethiEomeshi/lo dominant populations that efficiently recognized endogenous antigen demonstrated lower intrinsic avidity for pMHC, whereas T-betintEomeshi subdominant populations were characterized by higher pMHC avidity and less efficient recognition of virus-infected cells. Importantly, differential endogenous viral antigen recognition by CMV-specific CD8+ T cells also correlated with the differentiation status and expression of perforin, granzyme B and K. Furthermore, we demonstrate that the expression of T-bet correlates with clonal expansion, differentiation status, and expression of perforin, granzyme B and K in antigen-specific T cells. These findings illustrate how endogenous viral antigen presentation during persistent viral infection may influence the transcriptional program of virus-specific T cells and their functional profile in the peripheral blood of humans.

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