Rejection of immunogenic tumor clones is limited by clonal fraction

Tumors often co-exist with T cells that recognize somatically mutated peptides presented by cancer cells on major histocompatibility complex I (MHC-I). However, it is unknown why the immune system fails to eliminate immune-recognizable neoplasms before they manifest as frank disease. To understand the determinants of MHC-I peptide immunogenicity in nascent tumors, we tested the ability of thousands of MHC-I ligands to cause tumor subclone rejection in immunocompetent mice by use of a new ‘PresentER’ antigen presentation platform. Surprisingly, we show that immunogenic tumor antigens do not lead to immune-mediated cell rejection when the fraction of cells bearing each antigen (‘clonal fraction’) is low. Moreover, the clonal fraction necessary to lead to rejection of immunogenic tumor subclones depends on the antigen. These data indicate that tumor neoantigen heterogeneity has an underappreciated impact on immune elimination of cancer cells and has implications for the design of immunotherapeutics such as cancer vaccines.

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Therapeutic Cancer Vaccines in Combination with Conventional Therapy

Journal of Biomedicine and Biotechnology ◽

10.1155/2010/237623 ◽

2010 ◽

Vol 2010 ◽

pp. 1-10 ◽

Cited By ~ 20

Author(s):

Mads Hald Andersen ◽

Niels Junker ◽

Eva Ellebaek ◽

Inge Marie Svane ◽

Per thor Straten

Keyword(s):

Immune System ◽

Cancer Cells ◽

Clinical Efficacy ◽

Tumor Antigens ◽

Suppressor Cells ◽

Tumor Stroma ◽

Therapeutic Vaccines ◽

Immune Mediated ◽

Therapeutic Cancer Vaccines ◽

Target Cancer

The clinical efficacy of most therapeutic vaccines against cancer has not yet met its promise. Data are emerging that strongly support the notion that combining immunotherapy with conventional therapies, for example, radiation and chemotherapy may improve efficacy. In particular combination with chemotherapy may lead to improved clinical efficacy by clearing suppressor cells, reboot of the immune system, by rendering tumor cells more susceptible to immune mediated killing, or by activation of cells of the immune system. In addition, a range of tumor antigens have been characterized to allow targeting of proteins coupled to intrinsic properties of cancer cells. For example, proteins associated with drug resistance can be targeted, and form ideal target structures for use in combination with chemotherapy for killing of surviving drug resistant cancer cells. Proteins associated with the malignant phenotype can be targeted to specifically target cancer cells, but proteins targeted by immunotherapy may also simultaneously target cancer cells as well as suppressive cells in the tumor stroma.

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Major Histocompatibility Complex I Mediates Immunological Tolerance of the Trophoblast during Pregnancy and May Mediate Rejection during Parturition

Mediators of Inflammation ◽

10.1155/2014/579279 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Anna Rapacz-Leonard ◽

Małgorzata Dąbrowska ◽

Tomasz Janowski

Keyword(s):

Major Histocompatibility Complex ◽

Immune System ◽

Complex I ◽

Immunological Tolerance ◽

Physiological Changes ◽

Major Histocompatibility ◽

Mhc I ◽

Histocompatibility Complex ◽

Maternal Immune System ◽

Major Histocompatibility Complex I

During pregnancy in larger mammals, the maternal immune system must tolerate the fetus for months while resisting external infection. This tolerance is facilitated by immunological communication between the fetus and the mother, which is mediated by Major Histocompatibility Complex I (MHC I) proteins, by leukocytes, and by the cytokines secreted by the leukocytes. Fetal-maternal immunological communication also supports pregnancy by inducing physiological changes in the mother. If the mother “misunderstands” the signal sent by the fetus during pregnancy, the fetus will be miscarried or delivered preterm. Unlike any other maternal organ, the placenta can express paternal antigens. At parturition, paternal antigens are known to be expressed in cows and may be expressed in horses, possibly so that the maternal immune system will reject the placenta and help to expel it. This review compares fetal-maternal crosstalk that is mediated by the immune system in three species with pregnancies that last for nine months or longer: humans, cattle, and horses. It raises the possibility that immunological communication early in pregnancy may prepare the mother for successful expulsion of fetal membranes at parturition.

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Comprehensive mutagenesis identifies the peptide repertoire of a p53 T-cell receptor mimic antibody that displays no toxicity in mice transgenic for human HLA-A*0201

PLoS ONE ◽

10.1371/journal.pone.0249967 ◽

2021 ◽

Vol 16 (4) ◽

pp. e0249967

Author(s):

Iva Trenevska ◽

Amanda P. Anderson ◽

Carol Bentley ◽

Tasneem Hassanali ◽

Sarah Wiblin ◽

...

Keyword(s):

T Cell ◽

T Cell Receptor ◽

Tumor Antigens ◽

Mutational Analysis ◽

Cell Receptor ◽

Class I Mhc ◽

Mhc I ◽

Peptide Specificity ◽

Histocompatibility Complex

T-cell receptor mimic (TCRm) antibodies have expanded the repertoire of antigens targetable by monoclonal antibodies, to include peptides derived from intracellular proteins that are presented by major histocompatibility complex class I (MHC-I) molecules on the cell surface. We have previously used this approach to target p53, which represents a valuable target for cancer immunotherapy because of the high frequency of its deregulation by mutation or other mechanisms. The T1-116C TCRm antibody targets the wild type p5365-73 peptide (RMPEAAPPV) presented by HLA-A*0201 (HLA-A2) and exhibited in vivo efficacy against triple receptor negative breast cancer xenografts. Here we report a comprehensive mutational analysis of the p53 RMPEAAPPV peptide to assess the T1-116C epitope and its peptide specificity. Antibody binding absolutely required the N-terminal arginine residue, while amino acids in the center of the peptide contributed little to specificity. Data mining the immune epitope database with the T1-116C binding consensus and validation of peptide recognition using the T2 stabilization assay identified additional tumor antigens targeted by T1-116C, including WT1, gp100, Tyrosinase and NY-ESO-1. Most peptides recognized by T1-116C were conserved in mice and human HLA-A2 transgenic mice showed no toxicity when treated with T1-116C in vivo. We conclude that comprehensive validation of TCRm antibody target specificity is critical for assessing their safety profile.

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Plasma-Activated Medium Potentiates the Immunogenicity of Tumor Cell Lysates for Dendritic Cell-Based Cancer Vaccines

Cancers ◽

10.3390/cancers13071626 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1626

Author(s):

Sergej Tomić ◽

Anđelija Petrović ◽

Nevena Puač ◽

Nikola Škoro ◽

Marina Bekić ◽

...

Keyword(s):

T Cells ◽

Cancer Vaccines ◽

Mononuclear Cells ◽

Tumor Antigens ◽

Human Peripheral Blood ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Peripheral Blood Mononuclear ◽

Immunogenic Tumor ◽

Control Tumor

Autologous dendritic cells (DCs)-based vaccines are considered quite promising for cancer immunotherapy due to their exquisite potential to induce tumor antigen-specific cytotoxic T cells. However, a lack of efficient protocols for inducing immunogenic tumor antigens limits the efficacy of DC-based cancer vaccines. Here, we found that a plasma-activated medium (PAM) induces immunogenic cell death (ICD) in tumor cells but not in an immortalized L929 cell line or human peripheral blood mononuclear cells. PAM induced an accumulation of reactive oxygen species (ROS), autophagy, apoptosis, and necrosis in a concentration-dependent manner. The tumor lysates prepared after PAM treatment displayed increased immunogenicity in a model of human monocyte-derived DCs, compared to the lysates prepared by a standard freezing/thawing method. Mature DCs loaded with PAM lysates showed an increased maturation potential, as estimated by their increased expression of CD83, CD86, CD40, IL-12/IL-10 production, and attenuated PDL1 and ILT-4 expression, compared to the DCs treated with control tumor lysates. Moreover, in co-culture with allogeneic T cells, DCs loaded with PAM-lysates increased the proportion of cytotoxic IFN-γ+ granzyme A+ CD8+ T cells and IL-17A-producing T cells and preserved the Th1 response. In contrast, control tumor lysates-treated DCs increased the frequency of Th2 (CD4+IL-4+), CD4, and CD8 regulatory T cell subtypes, none of which was observed with DCs loaded with PAM-lysates. Cumulatively, these results suggest that the novel method for preparing immunogenic tumor lysates with PAM could be suitable for improved DC-based immunotherapy of cancer patients.

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785 STING-agonist ADCs targeting tumor-associated antigens coordinate immune-mediated killing of antigen-negative cancer cells

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.785 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A820-A820

Author(s):

Phonphimon Wongthida ◽

Kalli Catcott ◽

Kelly Lancaster ◽

Keith Bentley ◽

Anouk Dirksen ◽

...

Keyword(s):

Cancer Cells ◽

Immune Cells ◽

Tumor Antigens ◽

Minimal Impact ◽

Tumor Associated Antigens ◽

Immune Mediated ◽

Sting Pathway ◽

Anti Tumor Activity

BackgroundThe tumor microenvironment is a complex, multicellular system, composed not only of malignant cancer cells but also of a diversity of stromal cells including vascular cells, immune cells, and fibroblasts that support tumorigenesis. Antigens expressed on these cells tend to be widely expressed across a range of malignancies, presenting unique opportunities for development of anti-cancer therapies.MethodsWe have previously demonstrated that STING-agonist antibody-drug conjugates (Immunosynthen ADCs) targeting tumor cell antigens induce target-dependent anti-tumor immune responses in vitro and in vivo. To that effect, we hypothesized that Immunosynthen ADCs targeting tumor-associated antigens would coordinate immune-mediated killing of cancer cells not expressing the tumor-associated antigens (antigen-negative cancer cells) and induce anti-tumor activity.ResultsHerein, we demonstrate that targeting tumor-associated antigens with STING-agonist ADCs activate the STING pathway in immune cells via Fcγ receptor-mediated uptake. In addition, due to the intrinsic ability of certain tumor-associated cells to activate the STING pathway, STING-agonist ADCs targeting those cells can induce STING signaling in both the targeted cells and the immune cells, which constitutes a therapeutic advantage of ADCs that activate the STING pathway. In triple co-cultures of antigen-positive tumor-associated cells, antigen-negative cancer cells, and immune cells, the STING-agonist ADC specifically induced potent cell killing of the antigen-negative cancer cells with minimal impact on the immune and tumor-associated cells, thus representing a non-traditional, yet highly effective mechanism of ADC targeting. In vivo efficacy studies showed that STING-agonist ADCs developed for two tumor-associated antigens induced complete, sustained tumor regressions in syngeneic tumor models and exhibited immunological memory after rechallenge. CD8+ T cells contributed to the anti-tumor activity of the STING-agonist ADCs.ConclusionsIn summary, Immunosynthen STING-agonist ADCs targeting tumor-associated antigens represent a novel approach for ADC-mediated cancer immunotherapy and enable the multifaceted activation of the STING pathway in a tumor-targeted manner beyond tumor antigens.

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Major Histocompatibility Complex I and II Expression and Lymphocytic Subtypes in Muscle of Horses with Immune‐Mediated Myositis

Journal of Veterinary Internal Medicine ◽

10.1111/jvim.14371 ◽

2016 ◽

Vol 30 (4) ◽

pp. 1313-1321 ◽

Cited By ~ 9

Author(s):

S.A. Durward‐Akhurst ◽

C.J. Finno ◽

N. Barnes ◽

J. Shivers ◽

L.T. Guo ◽

...

Keyword(s):

Major Histocompatibility Complex ◽

Complex I ◽

Major Histocompatibility ◽

Histocompatibility Complex ◽

Immune Mediated ◽

Major Histocompatibility Complex I

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Absolute quantification of tumor antigens using embedded MHC-I isotopologue calibrants

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2111173118 ◽

2021 ◽

Vol 118 (37) ◽

pp. e2111173118

Author(s):

Lauren E. Stopfer ◽

Aaron S. Gajadhar ◽

Bhavin Patel ◽

Sebastien Gallien ◽

Dennie T. Frederick ◽

...

Keyword(s):

Melanoma Cell Line ◽

Tumor Antigens ◽

Internal Standard ◽

Mek Inhibitor ◽

Absolute Quantification ◽

Melanoma Tumor ◽

Mhc I ◽

Histocompatibility Complex ◽

Tumor Biopsies ◽

Targeted Immunotherapy

Absolute quantification measurements (copies per cell) of peptide major histocompatibility complex (pMHC) antigens are necessary to inform targeted immunotherapy drug design; however, existing methods for absolute quantification have critical limitations. Here, we present a platform termed SureQuant-IsoMHC, utilizing a series of pMHC isotopologues and internal standard-triggered targeted mass spectrometry to generate an embedded multipoint calibration curve to determine endogenous pMHC concentrations for a panel of 18 tumor antigens. We apply SureQuant-IsoMHC to measure changes in expression of our target panel in a melanoma cell line treated with a MEK inhibitor and translate this approach to estimate antigen concentrations in melanoma tumor biopsies.

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Ubiquitination of serine, threonine, or lysine residues on the cytoplasmic tail can induce ERAD of MHC-I by viral E3 ligase mK3

The Journal of Cell Biology ◽

10.1083/jcb.200611063 ◽

2007 ◽

Vol 177 (4) ◽

pp. 613-624 ◽

Cited By ~ 182

Author(s):

Xiaoli Wang ◽

Roger A. Herr ◽

Wei-Jen Chua ◽

Lonnie Lybarger ◽

Emmanuel J.H.J. Wiertz ◽

...

Keyword(s):

Complex I ◽

E3 Ligase ◽

Mhc I ◽

Endoplasmic Reticulum Associated Degradation ◽

Histocompatibility Complex ◽

Lysine Residues ◽

Ubiquitin Conjugation ◽

Infected Cells ◽

Immune Detection ◽

Major Histocompatibility Complex I

The mechanism by which substrates for endoplasmic reticulum–associated degradation are retrotranslocated to the cytosol remains largely unknown, although ubiquitination is known to play a key role. The mouse γ-herpesvirus protein mK3 is a viral RING-CH–type E3 ligase that specifically targets nascent major histocompatibility complex I heavy chain (HC) for degradation, thus blocking the immune detection of virus-infected cells. To address the question of how HC is retrotranslocated and what role mK3 ligase plays in this action, we investigated ubiquitin conjugation sites on HC using mutagenesis and biochemistry approaches. In total, our data demonstrate that mK3-mediated ubiquitination can occur via serine, threonine, or lysine residues on the HC tail, each of which is sufficient to induce the rapid degradation of HC. Given that mK3 has numerous cellular and viral homologues, it will be of considerable interest to determine the pervasiveness of this novel mechanism of ubiquitination.

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Ligand Design for Specific MHC Class I Molecules on the Cell Surface

10.26434/chemrxiv.12865688 ◽

2020 ◽

Author(s):

Xizheng Sun ◽

Reika Tokunaga ◽

Yoko Nagai ◽

Ryo Miyahara ◽

Akihiro Kishimura ◽

...

Keyword(s):

Cell Surface ◽

Mhc Class I ◽

Targeted Delivery ◽

Peptide Ligands ◽

Class I ◽

Class I Mhc ◽

Mhc I ◽

Histocompatibility Complex ◽

High Binding Affinity ◽

Mhc Class I Molecules

<p><a></a><a></a><a>We have validated that ligand peptides designed from antigen peptides could be used for targeting specific major histocompatibility complex class I (MHC-I)</a> molecules on cell surface. To design the ligand peptides, we used reported antigen peptides for each MHC-I molecule with high binding affinity. From the crystal structure of the peptide/MHC-I complexes, we determined a modifiable residue in the antigen peptides and replaced this residue with a lysine with an ε-amine group modified with functional molecules. The designed ligand peptides successfully bound to cells expressing the corresponding MHC-I molecules via exchange of peptides bound to the MHC-I. We demonstrated that the peptide ligands could be used to transport a protein or a liposome to cells expressing the corresponding MHC-I. The present strategy may be useful for targeted delivery to cells overexpressing MHC-I, which have been observed autoimmune diseases.</p>

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