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Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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bioRxiv2025

Generation of antigen-specific and functionally stable Treg cells from effector/memory T cells for cell therapy of immunological diseases

One strategy for antigen-specific immunosuppression is to convert antigen-specific conventional T cells (Tconvs) into Foxp3+ regulatory T cells (Tregs) that are as stably suppressive as naturally occurring Tregs (nTregs). To achieve the conversion in vitro for mice and humans, we induced high Foxp3 expression in antigen- and IL-2-stimulated Tconvs by CDK8/19 inhibition, and established Treg-specific epigenetic changes by depriving CD28 co-stimulation during in vitro Treg induction to specifically promote the expression of Treg signature genes, especially Foxp3. Repeating this process, with intermittent resting cultures containing IL-2 only, enabled in a short duration efficient conversion of naive as well as effector/memory CD4+ Tconvs, including Th1, Th2 and Th17 cells, into Foxp3+ Tregs, which were similar to nTregs in transcription and epigenetic modification. Induced Tregs (iTregs) thus generated were indeed functionally and phenotypically stable in vivo and effectively suppressed inflammatory bowel disease and graft-versus-host disease in mouse models. Adoptive cell therapy with such effector/memory Tconv-derived, functionally stable, iTregs would be able to achieve antigen- and disease-specific treatment of immunological diseases. One Sentence SummaryAntigen-specific and functionally stable Treg cells can be generated in vitro from effector/memory T cells for cell therapy of immunological diseases.

immunology↗

bioRxiv2018

Machine learning identifies the immunological signature of Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic disease, with a strongly debated pathophysiological origin. Both adaptive and innate immune processes have been proposed as primary drivers, which may account for the observed clinical heterogeneity, but few high-depth studies have been performed. Here we profiled the adaptive immune system of 85 JIA patients and 43 age-matched controls, identifying immunological changes unique to JIA and others common across a broad spectrum of childhood inflammatory diseases. The JIA immune signature was shared between clinically distinct subsets, but was accentuated in the systemic JIA patients and those patients with active disease. Despite the extensive overlap in the immunological spectrum exhibited by healthy children and JIA patients, machine learning analysis of the dataset proved capable of diagnosis of JIA patients with ~90% accuracy. These results pave the way for large-scale longitudinal studies of JIA, where machine learning could be used to predict immune signatures that correspond to treatment response group.

immunology↗

bioRxiv2018

Immunological Diversity with Similarity

A diverse immune repertoire is considered a hallmark of good health, but measuring diversity requires a framework that incorporates not only sequences relative frequencies but also their functional similarity to each other. Using experimentally measured dissociation constants from over 1,300 antibody-antigen and T-cell receptor (TCR)-peptide pairs, we developed a framework for functional immunological diversity based on binding and applied it to nearly 400 high-throughput antibody and TCR repertoires to reveal patterns in immunological memory, infection, vaccination, and aging. We show that functional diversity adds information that is not captured by raw diversity, revealing signatures of e.g. clonal selection, and that unlike raw diversity, functional diversity is a robust measure that does not require correction for sampling error. Finally, we show that according to functional diversity, unlike raw diversity, individuals repertoires overlap substantially, indicating a definable ceiling for the functional diversity of human adaptive immunity. Similarity redefines diversity in complex systems.

immunology↗

bioRxiv2019

A comprehensive atlas of immunological differences between humans, mice and non-human primates

Animal models are an integral part of the drug development and evaluation process. However, they are unsurprisingly imperfect reflections of humans, and the extent and nature of many immunological differences are unknown. With the rise of targeted and biological therapeutics, it is increasingly important that we understand the molecular differences in immunological behavior of humans and model organisms. Thus, we profiled a large number of healthy humans, along with three of the model organisms most similar to humans: rhesus and cynomolgus macaques and African green monkeys; and the most widely used mammalian model: mice. Using cross-species, universal phenotyping and signaling panels, we measured immune cell signaling responses to an array of 15 stimuli using CyTOF mass cytometry. We found numerous instances of different cellular phenotypes and immune signaling events occurring within and between species with likely effects on evaluation of therapeutics, and detail three examples (double-positive T cell frequency and signaling; granulocyte response to Bacillus anthracis antigen; and B cell subsets). We also explore the correlation of herpes simian B virus serostatus on the immune profile. The full dataset is available online at https://flowrepository.org (accession FR-FCM-Z2ZY) and https://immuneatlas.org.

immunology↗

bioRxiv2026

Interferon lambda drives immunological maturation in the infant lung and protects against lethal Bordetella pertussis infection

Serious pertussis infections disproportionately affect infants but the biological basis for this age-dependent susceptibility remains unclear. Infant mouse models recapitulate features of severe human infant pertussis. We investigated the role of interferon lambda (IFN-{lambda}), a key regulator of mucosal immunity, in Bordetella pertussis infection of infant mice. While infected adult mice upregulate lung IFN-{lambda}, infant mice inoculated at P7 fail to upregulate IFN-{lambda} and succumb to infection. We hypothesized that failure to produce IFN-{lambda} during infection represents a critical immunological deficit in infant mice, and that restoring IFN-{lambda} signaling would improve survival outcomes. Whereas wild-type mice gained complete protection from lethal B. pertussis infection by P10, mice lacking the IFN-{lambda} receptor component IFNLR1 did not achieve full protection until P21. Loss of IFNLR1 was associated with enhanced bacterial dissemination to systemic organs. Infant mice possessed a functional IFN-{lambda} receptor in the lungs but failed to upregulate IFN-{lambda} during infection, and supplementing IFN-{lambda} exogenously extended survival. RNA sequencing of lung tissue from infected and uninfected wild-type and IFNLR1-deficient mice inoculated at different ages identified an immune transcriptional framework distinguishing susceptible from resistant animals at a systems level and revealed IFN-{lambda} signaling as a critical driver of immunological maturation in the infant lung. Infected infant IFNLR1-deficient mice had dysregulated immune cell recruitment to the lungs, indicating a quantitatively expanded but qualitatively impaired response. These findings demonstrate that IFN-{lambda} affects immune maturation accounting for a critical window of age-dependent resistance to lethal pertussis with novel therapeutic possibilities for human infants with this disease.

immunology↗

bioRxiv2017

Immunological tolerance, pregnancy and pre-eclampsia: the roles of semen microbes and the father

Although it is widely recognised as involving two stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of pre-eclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its aetiology. However, apart from recognising, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focussed on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focussing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the fathers semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of preeclampsia. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother via insemination. O_QD\"In one of the last articles which he wrote, the late Professor F J Browne (1958) expressed the opinion that all the essential facts about pregnancy toxaemia are now available and that all that is required to solve the problem is to fit them together in the right order, like the pieces of a jigsaw puzzle\" [1]\n\nC_QD O_QD\"It appears astonishing how little attention has been given in reproductive medicine to the maternal immune system over the last few decades.\" [2]\n\nC_QD

microbiology↗

bioRxiv2020

Integrated multivariate analysis of transcriptomic data reveals immunological mechanisms in mice after Leishmania infantum infection

Transcriptional analysis of complex biological scenarios has been extensively used, even though sometimes results may prove imprecise or difficult-to interpret due to an overwhelming amount of information. In this study, a large-scale Real-time qPCR experiment was coupled to multivariate statistical analysis to describe the main immunological events underlying the early L. infantum infection in livers of BALB/c mice. High-throughput qPCR was used to evaluate the expression of 223 genes related to immunometabolism 1-, 3-, 5- and 10-days post infection. This integrative analysis showed strikingly different gene signatures at 1- and 10-days post infection, revealing progression of infection in the experimental model based on the upregulation of particular immunological response patterns and mediators. This approach addresses the challenge of integrating large collections of transcriptional data for the identification of candidate biomarkers in experimental models.

microbiology↗

bioRxiv2021

Caregiving quality modulates neuroendocrine and immunological markers in young children in foster care who have experienced early adversity

BackgroundEarly adversity is believed to alter the bodys stress response systems, putting children at increased risk for somatic and mental health problems. However, it remains unclear whether such alterations normalize under improved caregiving experiences. Thus, the goal of the present study was to investigate i) whether children in foster care show endocrine and immunological alterations relative to children living with their biological families, ii) whether these alterations change over time spent with the foster family and iii) whether the alterations are modulated by current caregiving experiences. MethodsA total of 94 children in foster care and 157 biological children, aged two to seven years, took part in a longitudinal study with three assessments conducted over a 12-month study period. At the initial assessment, children lived for an average of 18 months with their current foster families. Childrens cortisol, dehydroepiandrosterone (DHEA) and progesterone concentrations and cortisol/DHEA ratios were measured in scalp hair and childrens secretory immunoglobulin A (sIgA) levels in saliva. Caregiving quality was assessed based on caregiver-reports and observational measures of caregiver-child interactions. ResultsChildren in foster care had lower cortisol/DHEA ratios and higher progesterone concentrations than biological children, while no group differences were found for cortisol, DHEA or sIgA. Time spent with the current foster family did not significantly influence the childs endocrine or immunological markers. Importantly, caregiving quality modulated cortisol/DHEA ratios and sIgA concentrations: children in foster care of lower caregiving quality had lower cortisol/DHEA ratios than children in foster care of higher caregiving quality and showed decreasing, rather than increasing, sIgA concentrations across the study period. ConclusionsOur results indicate that caregiving quality in the foster family may have an important modulating effect on selected indicators of the childs stress response and could thereby mitigate the possible consequences of early childhood adversity.

physiology↗

bioRxiv2021

3D single molecule localization microscopy reveals the topography of the immunological synapse at isotropic precision below 15 nm

T-cells engage with antigen-presenting cells in search for antigenic peptides and form transient interfaces termed immunological synapses. A variety of protein-protein interactions in trans-configuration defines the topography of the synapse and orchestrates the antigen-recognition process. In turn, the synapse topography affects receptor binding rates and the mutual segregation of proteins due to size exclusion effects. For better understanding it is hence critical to map the 3D topography of the immunological synapse at high precision. Current methods, however, provide only rather coarse images of the protein distribution within the synapse, which do not reach the dimension of the protein ectodomains. Here, we applied supercritical angle fluorescence microscopy combined with defocused imaging, which allows 3-dimensional single molecule localization microscopy (3D-SMLM) at an isotropic localization precision below 15 nm. Experiments were performed on hybrid synapses between primary T-cells and functionalized glass-supported lipid bilayers. We used 3D-SMLM to quantify the cleft size within the synapse by mapping the position of the T-cell receptor (TCR) with respect to the supported lipid bilayer, yielding average distances of 18 nm up to 31 nm for activating and non-activating bilayers, respectively.

biophysics↗

bioRxiv2022

Development of a mouse salivary gland-derived mesenchymal cell line for immunological studies of murine cytomegalovirus

The salivary glands are a crucial site of replication for human cytomegalovirus (HCMV) and its murine counterpart, murine cytomegalovirus (MCMV). Studies of MCMV often involve the use of BALB/c strain mice, but most in vitro assays are carried out in the NIH 3T3 cell line, which is derived from Swiss Albino mice. This report describes a BALB/c-derived mouse salivary gland cell line immortalized using the SV40 large T antigen. Cells stained positive for PDGFR1 and negative for E-cadherin and PECAM-1, indicating mesenchymal origin. This cell line, which has been named murine salivary gland mesenchymal (mSGM), shows promise as a tool for ex vivo immunological assays due to its MHC haplotype match with the BALB/c mouse strain. In addition, plaque assays using mSGM rather than NIH 3T3 cells are significantly more sensitive for detecting low concentrations of MCMV particles. Finally, it is demonstrated that mSGM cells express all 3 BALB/c MHC class I isotypes and are susceptible to T cell-mediated ex vivo cytotoxicity assays, leading to many possible uses in immunological studies of MCMV.

microbiology↗

bioRxiv2022

BET inhibition sensitizes immunologically-cold Rb-deficient prostate cancer to immune checkpoint blockade

PurposeNon-T cell-inflamed immunologically "cold" tumor microenvironments (TME) are associated with poor responsiveness to immune checkpoint blockade (ICB), and can be sculpted by tumor cell genomics. Here we evaluated how Retinoblastoma (Rb) tumor suppressor loss of function (LOF), one of the most frequent alterations in human cancer and associated with lineage plasticity, poor prognosis and therapeutic outcomes, alters the TME, and whether therapeutic strategies targeting the molecular consequences of Rb loss enhance ICB efficacy. Experimental DesignWe performed bioinformatics analysis to elucidate the impact of endogenous Rb LOF on the immune TME in human primary and metastatic tumors. Next, we utilized isogenic murine models of Rb-deficient prostate cancer (PC) for in vitro and in vivo mechanistic studies to examine how Rb loss and bromodomain and extraterminal (BET) domain inhibition (BETi) reprograms the immune landscape, and evaluated in vivo therapeutic efficacy of BETi, singly and in combination with ICB and androgen deprivation therapy. ResultsRb loss was enriched in non-T cell-inflamed tumors, and Rb-deficient murine tumors demonstrated decreased immune infiltration in vivo. The BETi JQ1 increased immune infiltration into the TME through enhanced tumor cell STING/NF-{kappa}B activation and type I interferon (IFN) signaling within tumor cells, resulting in differential macrophage and T cell-mediated tumor growth inhibition and sensitization of Rb-deficient PC to ICB. ConclusionsBETi can reprogram the immunologically cold Rb-deficient TME via STING/NF-{kappa}B/IFN signaling to sensitize Rb-deficient PC to ICB. These data provide the mechanistic rationale to test combinations of BETi and ICB in clinical trials of Rb-deficient PC. STATEMENT OF TRANSLATIONAL RELEVANCERb LOF is one of the most common genomic alterations in human cancer, occurring in approximately 1/3 of advanced malignancies, Furthermore, loss of Rb correlates with enhanced aggressiveness and poor therapeutic outcomes. In this study, we demonstrate that loss of Rb is also associated with an immunosuppressive tumor microenvironment and lack of responsiveness to immune checkpoint blockade (ICB). As a strategy to overcome Rb LOF induced immunosuppression, we have demonstrated that BETi treatment drives STING/NF-{kappa}B signaling and type I interferon production within tumor cells, resulting in immune-mediated tumor control in Rb-deficient PC, which is accentuated by the combination with ICB and ADT. These findings provide a roadmap for maximizing the clinical translation of BET inhibitors into the clinic to treat aggressive-variant Rb-deficient PC.

cancer biology↗

bioRxiv2022

The baseline immunological and hygienic status of pigs impact disease severity of African swine fever

African Swine Fever virus (ASFV) is a large double-enveloped DNA virus of the Asfarviridae family that causes a lethal hemorrhagic disease in domestic pigs and wild boars. Since 2007, a highly virulent genotype II strain has emerged and spread in Europe and South-East Asia, where millions of animals succumbed to the disease. Field- and laboratory-attenuated strains of ASFV cause highly variable clinical disease severity and survival, and mechanisms remain unclear. We hypothesized that the immunological and hygienic status of pigs is a determinant of ASF disease course. Here we compared the immunological profile at baseline and in response to ASFV infection in specific pathogen-free (SPF) and farm-raised Large White domestic pigs. At steady state, SPF pigs showed lower white blood cell counts and a lower basal inflammatory and antiviral transcriptomic profile compared to farm pigs associated with profound differences in gut microbiome composition. After inoculation with a highly virulent ASFV genotype II strain (Armenia 2008), severe clinical signs, viremia and pro-inflammatory cytokines appeared sooner in SPF pigs, indicating a reduced capacity to control early virus replication. In contrast, during infection with an attenuated field isolate (Estonia 2014), SPF pigs presented a milder and shorter clinical disease with full recovery, whereas farm pigs presented severe protracted disease with 50% lethality. Interestingly, farm pigs showed higher production of inflammatory cytokines, whereas SPF pigs produced more anti-inflammatory IL-1ra early after infection, and presented a stronger expansion of leukocytes in the recovery phase. Altogether, our data indicate that the hygiene-dependent innate immune status has a double-edge sword impact on immune responses in ASF pathogenesis. While the higher baseline innate immune activity helps the host in reducing initial virus replication, it promotes immunopathological cytokine responses, and delays lymphocyte proliferation after infection with an attenuated strain. Such effects should be considered for live vaccine development and vigilance.

microbiology↗

bioRxiv2022

Evidence of divergent selection in a parasite due to its host immunological respond

We investigated if an immunological response (i.e. fibrosis) in threespine stickleback fish can cause divergent selection in its tapeworm Schistocephalus solidus. We pooled tapeworms from six populations in Vancouver Island (BC, Canada) and sequenced the whole genome of these pools. Then we used a modified Population Branch Statistics (PBS) technique based on FST comparisons to find loci under divergent selection due to fibrosis. We found at least eight loci under divergent selection in tapeworm populations caused by this strong immunological respond to infection from the fish.

evolutionary biology↗

bioRxiv2022

Structural and Immunological Similarities Between the Metacyclic and Bloodstream Form Variant Surface Glycoproteins of the African Trypanosome

During infection of mammalian hosts, African trypanosomes thwart immunity using antigenic variation of the dense Variant Surface Glycoprotein (VSG) coat, accessing a large repertoire of thousands of genes and pseudogenes and switching to antigenically distinct copies. The parasite is transferred to mammalian hosts through the bite of the tsetse fly. In the salivary glands of the fly, the pathogen adopts the metacyclic form and expresses a limited repertoire of VSG genes specific to that developmental stage. It has remained unknown whether the metacyclic VSGs possess distinct properties associated with this particular and discrete phase of the parasite life cycle. We show here using bioinformatic, crystallographic, and immunological analyses of three metacyclic VSGs that they closely mirror the known classes of bloodstream form VSGs both in structure and in the immunological responses they elicit.

microbiology↗

bioRxiv2022

scifAI: Explainable machine learning for profiling the immunological synapse and functional characterization of therapeutic antibodies

Therapeutic antibodies are widely used to treat severe diseases. Most of them alter immune cells and act within the immunological synapse; an essential cell-to-cell interaction to direct the humoral immune response. Although many antibody designs are generated and evaluated, a high-throughput tool for systematic antibody characterization and prediction of function is lacking. Here, we introduce the first comprehensive open-source framework, scifAI (single-cell imaging flow cytometry AI), for preprocessing, feature engineering and explainable, predictive machine learning on imaging flow cytometry (IFC) data. Additionally, we generate the largest publicly available IFC data set of the human immunological synapse containing over 2.8 million images. Using scifAI, we analyze class frequency- and morphological changes under different immune stimulation. T cell cytokine production across multiple donors and therapeutic antibodies is quantitatively predicted in vitro, linking morphological features with function and demonstrating the potential to significantly impact antibody design. scifAI is universally applicable to IFC data. Given its modular architecture it is straightforward to incorporate into existing workflows and analysis pipelines, e.g. for rapid antibody screening and functional characterization.

bioinformatics↗

bioRxiv2023

MerTK mediates the immunologically silent uptake of alpha-synuclein fibrils by human microglia

MerTK is a receptor tyrosine kinase that mediates the immunologically silent phagocytic uptake of diverse types of cellular debris. Highly expressed on the surface of microglial cell, MerTK is of importance in brain development, homeostasis, plasticity, and disease. Yet, involvement of this receptor in the clearance of protein aggregates that accumulate with aging and in neurodegenerative diseases has yet to be defined. The current study explored the function of MerTK in the microglial uptake of alpha-synuclein fibrils which play a causative role in the pathobiology of synucleinopathies. Using human primary and induced pluripotent stem cell-derived microglia, the MerTK- dependence of alpha-synuclein fibril internalization was investigated in vitro. Relevance of this pathway to synucleinopathies was assessed by analyzing MerTK expression in patient-derived cells and tissues. Pharmacological inhibition of MerTK and siRNA-mediated MERTK knockdown both caused a decreased rate of alpha-synuclein fibril internalization by human microglia. Consistent with the immunologically silent nature of MerTK-mediated phagocytosis, alpha-synuclein fibril internalization did not induce secretion of pro-inflammatory cytokines from microglia. In addition, burden analysis in two independent patient cohorts revealed a significant association between rare functionally deleterious MERTK variants and Parkinsons disease in one of the cohorts (p = 0.002). Accordingly, MERTK expression was significantly upregulated in nigral microglia from Parkinsons disease/Lewy body dementia patients compared to those from non-neurological control donors in a single-nuclei RNA-sequencing dataset (p = 5.08x10-21), and MerTK protein expression positively correlated with alpha-synuclein level in human cortex lysates (p = 0.0029). Taken together, our findings define a novel role for MerTK in mediating the uptake of alpha-synuclein aggregates by human microglia, with possible involvement in limiting alpha-synuclein spread in synucleinopathies such as Parkinsons disease.

cell biology↗

bioRxiv2023

Deep immunological imprinting due to the ancestral spike in the current bivalent COVID-19 vaccine

With the aim of broadening immune responses against the evolving SARS-CoV-2 Omicron variants, bivalent COVID-19 mRNA vaccines that encode the ancestral and Omicron BA.5 spike proteins have been authorized for clinical use, supplanting the original monovalent counterpart in numerous countries. However, recent studies have demonstrated that administering either a monovalent or bivalent vaccine as a fourth vaccine dose results in similar neutralizing antibody titers against the latest Omicron subvariants, raising the possibility of immunological imprinting. Utilizing binding immunoassays, pseudotyped virus neutralization assays, and antigenic mapping, we investigated antibody responses from 72 participants who received three monovalent mRNA vaccine doses followed by either a bivalent or monovalent booster, or who experienced breakthrough infections with the BA.5 or BQ subvariant after vaccinations with an original monovalent vaccine. Compared to a monovalent booster, the bivalent booster did not yield noticeably higher binding titers to D614G, BA.5, and BQ.1.1 spike proteins, nor higher virus-neutralizing titers against SARS-CoV-2 variants including the predominant XBB.1.5 and the emergent XBB.1.16. However, sera from breakthrough infection cohorts neutralized Omicron subvariants significantly better. Multiple analyses of these results, including antigenic mapping, made clear that inclusion of the ancestral spike prevents the broadening of antibodies to the BA.5 component in the bivalent vaccine, thereby defeating its intended goal. Our findings suggest that the ancestral spike in the current bivalent COVID-19 vaccine is the cause of deep immunological imprinting. Its removal from future vaccine compositions is therefore strongly recommended.

microbiology↗

bioRxiv2024

Combination of oncolytic Maraba virus with immune checkpoint blockade overcomes therapy resistance in an immunologically cold model of advanced melanoma with dysfunctional T cell receptor signalling.

BackgroundOver the past decade, cancer immunotherapies have revolutionised the treatment of melanoma; however, responses vary across patient populations. Recently, baseline tumour size has been identified as an independent prognostic factor for overall survival in melanoma patients receiving immune checkpoint inhibitors (ICIs). MG1 is a novel oncolytic agent with broad tumour tropism that has recently entered early phase clinical trials. The aim of this study was to characterise T cell responses in human and mouse melanoma models following MG1 treatment and to establish if features of the tumour immune microenvironment (TIME) at two distinct tumour burdens would impact the efficacy of oncolytic virotherapy. MethodsHuman 3D in vitro priming assays were performed to measure anti-tumour and anti-viral T cell responses following MG1 infection. TCR sequencing, T2 killing assay, and peptide recall assays were used to assess the evolution of the TCR repertoire, and measure specific T cell responses, respectively. In vivo, subcutaneous 4434 melanomas were characterised using RNAseq, immunohistochemistry (IHC), and flow cytometry. The effectiveness of intra-tumoural MG1 was assessed in advancing 4434 tumours and the generation of anti-tumour and anti-viral T cells measured by splenocyte recall assays. Finally, combination MG1 and -PD-1 therapy was investigated in advanced 4434 tumours. ResultsMG1 effectively primed functional cytotoxic T cells (CTLs) against tumour associated antigens (TAA) as well as virus-derived peptides, as assessed using peptide recall and T2 killing assays, respectively. TCR sequencing revealed that MG1-primed CTL comprised larger clusters of similar CDR3 amino acid sequences compared to controls. In vivo testing of MG1 demonstrated that MG1 monotherapy was highly effective at treating early disease, resulting in 90% cures; however, the efficacy of MG1 reduced as the disease burden (local tumour size) increased, and the addition of -PD-1 was required to overcome resistance in more advanced disease. Differential gene expression profiles revealed that increased tumour burden was associated with an immunologically colder TIME. Furthermore, analysis of TCR signalling in advancing tumours demonstrated a different dynamic of TCR engagement compared to smaller tumours, in particular a shift in antigen recognition by CD4+ cells, from conventional to regulatory subset. ConclusionCombination of MG1 with PD-1 overcomes therapy resistance in an immunologically cold model of advanced melanoma.

cancer biology↗