scholarly journals P04.06 mucosal immunization with a cDC1-targeted CTA1 adjuvant vaccine confers protection against melanoma metastasis

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A39.1-A39
Author(s):  
M Arabpour ◽  
S Paul ◽  
R Kiffin ◽  
HG Wiktorin ◽  
K Hellstrand ◽  
...  

BackgroundSpecific targeting of anti-cancer vaccines to dendritic cells (DCs) has been shown to mount efficient immune responses against tumor cells. Classical CD103+dendritic cells (also called cDC1) have an inherent ability to cross-present antigens to CD8+ cytotoxic T cells. Here we have explored an anti-tumor vaccine that specifically targets cDC1 cells for protection against and elimination of metastatic melanoma. The vaccine contains the cholera toxin A1 subunit (CTA1) adjuvant and is targeted to cDC1 cells through an anti-CD103 single chain antibody (CD103 scFv).Material and MethodsC57BL/6 mice were injected with wild type or ovalbumin (OVA) expressing B16 melanoma cells either subcutaneously (s.c.) to establish solid tumors, or intravenously (i.v.) to allow the formation of pulmonary metastases. Before or after establishment of tumors, mice were intra-nasally inoculated with a vaccine composed of a CD103 scFv element fused to the adjuvant CTA1 and the MHC I H2kd-restricted OVA epitope SIINFEKL together with the MHC II H2kd-restricted OVA epitope p323 or just the p323 peptide alone (i.e. CTA1-SIINFEKL-p323-CD103 and CTA1-p323-CD103, respectively). Control mice were inoculated with PBS. The growth of solid tumors was carefully monitored and the development of pulmonary metastases was determined 2–3 weeks after tumor cell injection. In addition, antigen-specific T cell immunity following intranasal immunization was evaluated.ResultsTargeting MHC I and MHC II tumor cell epitopes to cDC1, via CD103 ScFv, in conjunction with the CTA1 adjuvant elicited strong tumor specific and protective CD8+ T cell responses as well as CD4+ T cell immunity. Immunization with the CTA1-SIINFEKL-p323-CD103 vaccine significantly reduced the growth of established solid B16F1-OVA melanomas (P<0.001) and potently prevented metastasis formation (P<0.01). Control immunizations with the CTA1-p323-CD103 vaccine tended to reduce metastasis, but tumor-specific CD8+ T cells were required for full therapeutic protection.ConclusionTargeting tumor specific CD8+ T cell epitopes to cDC1, in the context of a powerful adjuvant such as CTA1, leads to the development of efficient anti-tumor immune responses. Our results point towards the utility of cDC1-targeted vaccines in the treatment of established tumors or as a means to prevent metastasis formation.Disclosure InformationM. Arabpour: None. S. Paul: None. R. Kiffin: None. H.G. Wiktorin: None. K. Hellstrand: None. N. Lycke: None. A. Martner: None.

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A574-A574
Author(s):  
Ellen Duong ◽  
Timothy Fessenden ◽  
Arjun Bhutkar ◽  
Stefani Spranger

BackgroundCytotoxic (CD8+) T-cells are required for tumor eradication and durable anti-tumor immunity.1 The induction of tumor-reactive CD8+ T-cells is predominately attributed to a subset of dendritic cells (DC) called Batf3-driven DC1, given their robust ability to cross-present antigens for T-cell priming and their role in effector T-cell recruitment.2–4 Presence of the DC1 signature in tumors correlates with improved survival and response to immunotherapies.5–7 Yet, most tumors with a DC1 infiltrate still progress, suggesting that while DC1 can initiate tumor-reactive CD8+ T-cell responses, they are unable to sustain them. Therefore, there is a critical need to identify and engage additional stimulatory DC subsets to strengthen anti-tumor immunity and boost immunotherapy responses.MethodsTo identify DC subsets that drive poly-functional CD8+ T-cell responses, we compared the DC infiltrate of a spontaneously regressing tumor with a progressing tumor. Multicolor flow immunophenotyping and single-cell RNA-sequencing were used to profile the DC compartment of both tumors. IFNγ-ELISpot was performed on splenocytes to assess for systemic tumor-reactive T-cell responses. Sorted DC subsets from tumors were co-cultured with TCR-transgenic T-cells ex vivo to evaluate their stimulatory capacity. Cross-dressing (in vivo/ex vivo) was assayed by staining for transfer of tumor-derived H-2b MHC complexes to Balb/c DC, which express the H-2d haplotype. Protective systemic immunity was assayed via contralateral flank tumor outgrowth experiments.ResultsRegressor tumors were infiltrated with more cross-presenting DC1 than progressor tumors. However, tumor-reactive CD8+ T-cell responses and tumor control were preserved in Batf3-/- mice lacking DC1, indicating that anti-tumor immune responses could be induced independent of DC1. Through functional assays, we established that anti-tumor immunity against regressor tumors required CD11c+ DC and cGAS/STING-independent type-I-interferon-sensing. Single-cell RNA-sequencing of the immune infiltrate of regressor tumors revealed a novel CD11b+ DC subset expressing an interferon-stimulated gene signature (ISG+ DC). Flow studies demonstrated that ISG+ DC were more enriched in regressor tumors than progressor tumors. We showed that ISG+ DC could activate CD8+ T-cells by cross-dressing with tumor-derived peptide-MHC complexes, thereby bypassing the requirement for cross-presentation to initiate CD8+ T-cell-driven immunity. ISG+ DC highly expressed cytosolic dsRNA sensors (RIG-I/MDA5) and could be therapeutically harnessed by exogenous addition of a dsRNA analog to drive protective CD8+ T-cell responses in DC1-deficient mice.ConclusionsThe DC infiltrate in tumors can dictate the strength of anti-tumor immunity. Harnessing multiple stimulatory DC subsets, such as cross-presenting DC1 and cross-dressing ISG+ DC, provides a therapeutic opportunity to enhance anti-tumor immunity and increase immunotherapy responses.ReferencesFridman WH, et al. The immune contexture in human tumours: impact on clinical outcome. Nature Reviews Cancer 2012;12(4): p. 298–306.Hildner K, et al. Batf3 deficiency reveals a critical role for CD8alpha+ dendritic cells in cytotoxic T cell immunity. Science 2008;322(5904):p. 1097–100.Spranger S, et al. Tumor-Residing Batf3 dendritic cells are required for effector T cell trafficking and adoptive T cell therapy. Cancer Cell 2017;31(5):p. 711–723.e4.Roberts, EW, et al., Critical role for CD103(+)/CD141(+) dendritic cells bearing CCR7 for tumor antigen trafficking and priming of T cell immunity in melanoma. Cancer Cell 2016;30(2): p. 324–336.Broz ML, et al. Dissecting the tumor myeloid compartment reveals rare activating antigen-presenting cells critical for T cell immunity. Cancer Cell 2014;26(5): p. 638–52.Salmon H., et al., Expansion and activation of CD103(+) dendritic cell progenitors at the tumor site enhances tumor responses to therapeutic PD-L1 and BRAF inhibition. Immunity, 2016. 44(4): p. 924–38.Sánchez-Paulete AR, et al., Cancer immunotherapy with immunomodulatory anti-CD137 and Anti-PD-1 monoclonal antibodies requires BATF3-dependent dendritic cells. Cancer Discov, 2016;6(1):p. 71–9.


Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 706
Author(s):  
Chunmei Fu ◽  
Li Zhou ◽  
Qing-Sheng Mi ◽  
Aimin Jiang

As the sentinels of the immune system, dendritic cells (DCs) play a critical role in initiating and regulating antigen-specific immune responses. Cross-priming, a process that DCs activate CD8 T cells by cross-presenting exogenous antigens onto their MHCI (Major Histocompatibility Complex class I), plays a critical role in mediating CD8 T cell immunity as well as tolerance. Current DC vaccines have remained largely unsuccessful despite their ability to potentiate both effector and memory CD8 T cell responses. There are two major hurdles for the success of DC-based vaccines: tumor-mediated immunosuppression and the functional limitation of the commonly used monocyte-derived dendritic cells (MoDCs). Due to their resistance to tumor-mediated suppression as inert vesicles, DC-derived exosomes (DCexos) have garnered much interest as cell-free therapeutic agents. However, current DCexo clinical trials have shown limited clinical benefits and failed to generate antigen-specific T cell responses. Another exciting development is the use of naturally circulating DCs instead of in vitro cultured DCs, as clinical trials with both human blood cDC2s (type 2 conventional DCs) and plasmacytoid DCs (pDCs) have shown promising results. pDC vaccines were particularly encouraging, especially in light of promising data from a recent clinical trial using a human pDC cell line, despite pDCs being considered tolerogenic and playing a suppressive role in tumors. However, how pDCs generate anti-tumor CD8 T cell immunity remains poorly understood, thus hindering their clinical advance. Using a pDC-targeted vaccine model, we have recently reported that while pDC-targeted vaccines led to strong cross-priming and durable CD8 T cell immunity, cross-presenting pDCs required cDCs to achieve cross-priming in vivo by transferring antigens to cDCs. Antigen transfer from pDCs to bystander cDCs was mediated by pDC-derived exosomes (pDCexos), which similarly required cDCs for cross-priming of antigen-specific CD8 T cells. pDCexos thus represent a new addition in our arsenal of DC-based cancer vaccines that would potentially combine the advantage of pDCs and DCexos.


Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1687
Author(s):  
Magalie Dosset ◽  
Andrea Castro ◽  
Hannah Carter ◽  
Maurizio Zanetti

Telomerase reverse transcriptase (TERT) is a conserved self-tumor antigen which is overexpressed in most tumors and plays a critical role in tumor formation and progression. As such, TERT is an antigen of great relevance to develop widely applicable immunotherapies. CD4 T cells play a major role in the anti-cancer response alone or with other effector cells such as CD8 T cells and NK cells. To date, efforts have been made to identify TERT peptides capable of stimulating CD4 T cells that are also able to bind diverse MHC-II alleles to ease immune status monitoring and immunotherapies. Here, we review the current status of TERT biology, TERT/MHC-II immunobiology, and past and current vaccine clinical trials. We propose that monitoring CD4 T cell immunity against TERT is a simple and direct way to assess immune surveillance in cancer patients and a new way to predict the response to immune checkpoint inhibitors (ICPi). Finally, we present the initial results of a systematic discovery of TERT peptides able to bind the most common HLA Class II alleles worldwide and show that the repertoire of MHC-II TERT peptides is wider than currently appreciated.


2022 ◽  
Vol 12 ◽  
Author(s):  
Valentina Ceglia ◽  
Sandra Zurawski ◽  
Monica Montes ◽  
Mitchell Kroll ◽  
Aurélie Bouteau ◽  
...  

CD40 is a potent activating receptor expressed on antigen-presenting cells (APCs) of the immune system. CD40 regulates many aspects of B and T cell immunity via interaction with CD40L expressed on activated T cells. Targeting antigens to CD40 via agonistic anti-CD40 antibody fusions promotes both humoral and cellular immunity, but current anti-CD40 antibody-antigen vaccine prototypes require co-adjuvant administration for significant in vivo efficacy. This may be a consequence of dulling of anti-CD40 agonist activity via antigen fusion. We previously demonstrated that direct fusion of CD40L to anti-CD40 antibodies confers superagonist properties. Here we show that anti-CD40-CD40L-antigen fusion constructs retain strong agonist activity, particularly for activation of dendritic cells (DCs). Therefore, we tested anti-CD40-CD40L antibody fused to antigens for eliciting immune responses in vitro and in vivo. In PBMC cultures from HIV-1-infected donors, anti-CD40-CD40L fused to HIV-1 antigens preferentially expanded HIV-1-specific CD8+ T cells versus CD4+ T cells compared to analogous anti-CD40-antigen constructs. In normal donors, anti-CD40-CD40L-mediated delivery of Influenza M1 protein elicited M1-specific T cell expansion at lower doses compared to anti-CD40-mediated delivery. Also, on human myeloid-derived dendritic cells, anti-CD40-CD40L-melanoma gp100 peptide induced more sustained Class I antigen presentation compared to anti-CD40-gp100 peptide. In human CD40 transgenic mice, anti-CD40-CD40L-HIV-1 gp140 administered without adjuvant elicited superior antibody responses compared to anti-CD40-gp140 antigen without fused CD40L. In human CD40 mice, compared to the anti-CD40 vehicle, anti-CD40-CD40L delivery of Eα 52-68 peptide elicited proliferating of TCR I-Eα 52-68 CD4+ T cells producing cytokine IFNγ. Also, compared to controls, only anti-CD40-CD40L-Cyclin D1 vaccination of human CD40 mice reduced implanted EO771.LMB breast tumor cell growth. These data demonstrate that human CD40-CD40L antibody fused to antigens maintains highly agonistic activity and generates immune responses distinct from existing low agonist anti-CD40 targeting formats. These advantages were in vitro skewing responses towards CD8+ T cells, increased efficacy at low doses, and longevity of MHC Class I peptide display; and in mouse models, a more robust humoral response, more activated CD4+ T cells, and control of tumor growth. Thus, the anti-CD40-CD40L format offers an alternate DC-targeting platform with unique properties, including intrinsic adjuvant activity.


2020 ◽  
Vol 21 (17) ◽  
pp. 6144 ◽  
Author(s):  
Freya R. Shepherd ◽  
James E. McLaren

The human body frequently encounters harmful bacterial pathogens and employs immune defense mechanisms designed to counteract such pathogenic assault. In the adaptive immune system, major histocompatibility complex (MHC)-restricted αβ T cells, along with unconventional αβ or γδ T cells, respond to bacterial antigens to orchestrate persisting protective immune responses and generate immunological memory. Research in the past ten years accelerated our knowledge of how T cells recognize bacterial antigens and how many bacterial species have evolved mechanisms to evade host antimicrobial immune responses. Such escape mechanisms act to corrupt the crosstalk between innate and adaptive immunity, potentially tipping the balance of host immune responses toward pathological rather than protective. This review examines the latest developments in our knowledge of how T cell immunity responds to bacterial pathogens and evaluates some of the mechanisms that pathogenic bacteria use to evade such T cell immunosurveillance, to promote virulence and survival in the host.


2018 ◽  
Author(s):  
Thi Thu Phuong Tran ◽  
Karsten Eichholz ◽  
Patrizia Amelio ◽  
Crystal Moyer ◽  
Glen R Nemerow ◽  
...  

AbstractFollowing repeated encounters with adenoviruses most of us develop robust humoral and cellular immune responses that are thought to act together to combat ongoing and subsequent infections. Yet in spite of robust immune responses, adenoviruses establish subclinical persistent infections that can last for decades. While adenovirus persistence pose minimal risk in B-cell compromised individuals, if T-cell immunity is severely compromised, reactivation of latent adenoviruses can be life threatening. This dichotomy led us to ask how anti-adenovirus antibodies influence adenovirus-specific T-cell immunity. Using primary human blood cells, transcriptome and secretome profiling, and pharmacological, biochemical, genetic, molecular, and cell biological approaches, we initially found that healthy adults harbor adenovirus-specific regulatory T cells (Tregs). As peripherally induced Tregsare generated by tolerogenic dendritic cells (DCs), we then addressed how tolerogenic DCs could be created. Here, we demonstrate that DCs that take up immunoglobulin-complexed (IC)-adenoviruses create an environment that causes bystander DCs to become tolerogenic. These adenovirus antigen-loaded tolerogenic DCs can drive naïve T cells to mature into adenovirus-specific Tregs. Our results may provide ways to improve antiviral therapy and/or pre-screening high-risk individuals undergoing immunosuppression.Author summaryWhile numerous studies have addressed the cellular and humoral response to primary virus encounters, relatively little is known about the interplay between persistent infections, neutralizing antibodies, antigen-presenting cells, and the T-cell response. Our studies suggests that if adenovirus–antibody complexes are taken up by professional antigen-presenting cells (dendritic cells), the DCs generate an environment that causes bystander dendritic cells to become tolerogenic. These tolerogenic dendritic cells favors the creation of adenovirus-specific regulatory T cells. While this pathway likely favors pathogen survival, there may be advantages for the host also.


2002 ◽  
Vol 76 (10) ◽  
pp. 5062-5070 ◽  
Author(s):  
Pablo Sarobe ◽  
Juan José Lasarte ◽  
Noelia Casares ◽  
Ascensión López-Díaz de Cerio ◽  
Elena Baixeras ◽  
...  

ABSTRACT Patients infected with hepatitis C virus (HCV) have an impaired response against HCV antigens while keeping immune competence for other antigens. We hypothesized that expression of HCV proteins in infected dendritic cells (DC) might impair their antigen-presenting function, leading to a defective anti-HCV T-cell immunity. To test this hypothesis, DC from normal donors were transduced with an adenovirus coding for HCV core and E1 proteins and these cells (DC-CE1) were used to stimulate T lymphocytes. DC-CE1 were poor stimulators of allogeneic reactions and of autologous primary and secondary proliferative responses. Autologous T cells stimulated with DC-CE1 exhibited a pattern of incomplete activation characterized by enhanced CD25 expression but reduced interleukin 2 production. The same pattern of incomplete lymphocyte activation was observed in CD4+ T cells responding to HCV core in patients with chronic HCV infection. However, CD4+ response to HCV core was normal in patients who cleared HCV after alpha interferon therapy. Moreover, a normal CD4+ response to tetanus toxoid was found in both chronic HCV carriers and patients who had eliminated the infection. Our results suggest that expression of HCV structural antigens in infected DC disturbs their antigen-presenting function, leading to incomplete activation of anti-HCV-specific T cells and chronicity of infection. However, presentation of unrelated antigens by noninfected DC would allow normal T-cell immunity to other pathogens.


Blood ◽  
2010 ◽  
Vol 115 (8) ◽  
pp. 1554-1563 ◽  
Author(s):  
Stefania Parlato ◽  
Giulia Romagnoli ◽  
Francesca Spadaro ◽  
Irene Canini ◽  
Paolo Sirabella ◽  
...  

Abstract The identification of molecules responsible for apoptotic cell (AC) uptake by dendritic cells (DCs) and induction of T-cell immunity against AC-associated antigens is a challenge in immunology. DCs differentiated in the presence of interferon-α (IFN-α–conditioned DCs) exhibit a marked phagocytic activity and a special attitude in inducing CD8+ T-cell response. In this study, we found marked overexpression of the scavenger receptor oxidized low-density lipoprotein receptor 1 (LOX-1) in IFN-α–conditioned DCs, which was associated with increased levels of genes belonging to immune response families and high competence in inducing T-cell immunity against antigens derived from allogeneic apoptotic lymphocytes. In particular, the capture of ACs by IFN-α DCs led to a substantial subcellular rearrangement of major histocompatibility complex class I and class II molecules, along with enhanced cross-priming of autologous CD8+ T cells and CD4+ T-cell activation. Remarkably, AC uptake, CD8+ T-cell cross-priming, and, to a lesser extent, priming of CD4+ T lymphocytes were inhibited by a neutralizing antibody to the scavenger receptor LOX-1 protein. These results unravel a novel LOX-1–dependent pathway by which IFN-α can, under both physiologic and pathologic conditions, render DCs fully competent for presenting AC-associated antigens for cross-priming CD8+ effector T cells, concomitantly with CD4+ T helper cell activation.


Blood ◽  
2010 ◽  
Vol 116 (10) ◽  
pp. 1685-1697 ◽  
Author(s):  
Eynav Klechevsky ◽  
Anne-Laure Flamar ◽  
Yanying Cao ◽  
Jean-Philippe Blanck ◽  
Maochang Liu ◽  
...  

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.


2015 ◽  
Vol 11 (6) ◽  
pp. e1004930 ◽  
Author(s):  
Enrique Martin-Gayo ◽  
Maria Jose Buzon ◽  
Zhengyu Ouyang ◽  
Taylor Hickman ◽  
Jacqueline Cronin ◽  
...  

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