Negative Selection Process Research Articles

Type B thymomas in patients with myasthenia gravis display a distinctive pattern of αβ TCR and IL-7 receptor α expression on CD4+CD8+ thymocytes

Thymoma is closely associated with myasthenia gravis (MG). However, due to the heterogeneity of thymoma and the intricate pathogenesis of MG, it remains unclear why some patients with thymoma develop MG and others do not. In this study, we conducted a comparative phenotype analysis of thymocytes in type B thymomas in patients with MG (MG (+) thymomas) and without MG (MG (−) thymomas) via fluorescence-activated cell sorting (FACS). Our results show that the developmental stages defined by the expression of CD3, CD4, and CD8 were largely maintained in both MG (+) and MG (−) thymomas, with CD4+CD8+ cells constituting the majority of thymocytes in type B thymoma, and no significant difference between this cell population was observed in MG (+) and MG (−) thymomas.We discovered that CD4+CD8+ thymocytes in MG (+) thymomas expressed low levels of αβ TCR and high levels of IL-7 receptor α (IL-7Rα), whereas in MG (−) thymomas, CD4+CD8+ thymocytes exhibited the opposite pattern of αβ TCR and IL-7Rα expression. These results suggest that the positive and negative selection processes of CD4+CD8+ thymocytes might differ between MG (+) thymomas and MG (−) thymomas. The expression of the Helios transcription factor is induced during negative selection and marks a group of T cells that have undergone negative selection and are likely to be deleted due to strong TCR binding with self-peptides/MHC ligands. We observed that the percentage of Helios-positive CD4SP T cells was greater in MG (−) than in MG (+) thymomas. Thus, the differentially regulated selection process of CD4+CD8+ thymocytes, which involves TCR and IL-7/IL-7Rα signaling, is associated with the presence of MG in type B thymomas.

Abstract 4955: An analytic pipeline of neoantigen selection for both MHC-I and MHC-II pathways

Abstract Background: Accurate neoantigen selection is pivotal for assessing mutation burden and optimizing cancer vaccine formulation thereby playing a crucial role in cancer immunotherapy. The concurrent activation of CD4+ and CD8+ T cells engenders a robust immune response, which is key to effective treatment. However, currently analytic tools predominantly focus on the MHC-I pathway, typically relying on metrics such as gene expression level and MHC-binding affinity of mutated peptides. To address this gap, our study presents a comprehensive pipeline that encompasses both MHC-I and MHC-II pathways and integrates three critical dimensions of immune response: neoantigen abundance, presentation, and immunogenicity. Methods: We estimated mutated peptide abundance by analyzing genomic allelic frequency, transcriptomic allelic frequency, and RNA expression level. Antigen presentation was assessed using the patient harmonic binding rank (PHBR, a composite binding score for all potential MHC-peptide pairs) and MHC diversity (the variety of MHC alleles involved in peptide binding), with additional consideration for the loss of heterozygosity of MHC-I alleles, potentially indicative of immune escape. For immunogenicity, we factored in agretopicity (comparison of MHC-binding affinity between mutated and wild-type peptides), foreignness (similarity to immunogenic foreign antigens), and dissimilarity (sequence disparity with self-peptides, reflecting T cell negative selection process). Results: Implementing our pipeline on a dataset from Parkhurst et al. (2019), we analyzed immune reactivity in relation to 11,537 somatic mutations from 75 gastrointestinal cancer patients. Key metrics—RNA expression, transcriptomic allelic frequencies, PHBR, and MHC diversity—demonstrated significant correlations with both CD4+ and CD8+ activity (p<0.05). Notably, genomic allelic frequency was a significant factor in CD8+ reactivity, whereas agretopicity was crucial for CD4+ reactivity. Conclusion: Our pipeline elucidates the necessity for implementing both MHC-I and MHC-II pathway analyses to effectively select neoantigen candidates for CD8+ and CD4+ T cells respectively. The study confirms that abundance and antigen presentation metrics are robust indicators of neoantigen immunogenicity, supporting their use as potential markers in crafting more effective cancer vaccines. The findings highlight the critical role of this dual-pathway selection approach in generating a comprehensive immune response through neoantigen vaccination. Citation Format: Ko-Han Lee, Timothy Sears, Andrea Castro, Maurizio Zanetti, Hannah Carter. An analytic pipeline of neoantigen selection for both MHC-I and MHC-II pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4955.

SHAP value-based ERP analysis (SHERPA): Increasing the sensitivity of EEG signals with explainable AI methods

Conventionally, event-related potential (ERP) analysis relies on the researcher to identify the sensors and time points where an effect is expected. However, this approach is prone to bias and may limit the ability to detect unexpected effects or to investigate the full range of the electroencephalography (EEG) signal. Data-driven approaches circumvent this limitation, however, the multiple comparison problem and the statistical correction thereof affect both the sensitivity and specificity of the analysis. In this study, we present SHERPA – a novel approach based on explainable artificial intelligence (XAI) designed to provide the researcher with a straightforward and objective method to find relevant latency ranges and electrodes. SHERPA is comprised of a convolutional neural network (CNN) for classifying the conditions of the experiment and SHapley Additive exPlanations (SHAP) as a post hoc explainer to identify the important temporal and spatial features. A classical EEG face perception experiment is employed to validate the approach by comparing it to the established researcher- and data-driven approaches. Likewise, SHERPA identified an occipital cluster close to the temporal coordinates for the N170 effect expected. Most importantly, SHERPA allows quantifying the relevance of an ERP for a psychological mechanism by calculating an ”importance score”. Hence, SHERPA suggests the presence of a negative selection process at the early and later stages of processing. In conclusion, our new method not only offers an analysis approach suitable in situations with limited prior knowledge of the effect in question but also an increased sensitivity capable of distinguishing neural processes with high precision.

Integrated Human Skin Bacteria Genome Catalog Reveals Extensive Unexplored Habitat-Specific Microbiome Diversity and Function.

The skin is the largest organ in the human body. Various skin environments on its surface constitutes a complex ecosystem. One of the characteristics of the skin micro-ecosystem is low biomass, which greatly limits a comprehensive identification of the microbial species through sequencing. In this study, deep-shotgun sequencing (average 21.5Gigabyte (Gb)) from 450 facial samples and publicly available skin metagenomic datasets of 2069 samples to assemble a Unified Human Skin Genome (UHSG) catalog is integrated. The UHSG encompasses 813 prokaryotic species derived from 5779 metagenome-assembled genomes, among which 470 are novel species covering 20 phyla with 1385 novel assembled genomes. Based on the UHSG, the core functions of the skin microbiome are described and the differences in amino acid metabolism, carbohydrate metabolism, and drug resistance functions among different phyla are identified. Furthermore, analysis of secondary metabolites of the near-complete genomes further find 1220 putative novel secondary metabolites, several of which are found in previously unknown genomes. Single nucleotide variant (SNV) reveals a possible skin protection mechanism: the negative selection process of the skin environment to conditional pathogens. UHSG offers a convenient reference database that will facilitate a more in-depth understanding of the role of skin microorganisms in the skin.

Insights into B-cell ontogeny inferred from human immunology.

Due to ontogenetic changes in B-cell developmental lineages, the mature B-cell compartment constitutes by functionally different B-cell subsets that emerged from prenatal, early postnatal or adult precursors. While negative selection processes operate primarily within the framework of B-cell tolerance checkpoints during B-cell development, further differentiation into distinct B-cell subsets is additionally induced by positive selection. In addition to endogenous antigens, contact with microbial antigens is also involved in this selection process, with intestinal commensals having a significant influence on the development of a large layer within the B-cell compartment. The decisive threshold that triggers negative selection seems to be relaxed during fetal B-cell development, thereby allowing recruitment of polyreactive and also autoreactive B-cell clones into the mature naïve B-cell compartment. Almost all of the concepts on B-cell ontogeny are based on observations in laboratory mice that not only differ from humans in their developmental timeline but also in their composition of commensal microorganisms or rather a lack of exposure to these. In this review, we summarize conceptual findings on B-cell ontogeny and particularly describe key insights into the developing human B-cell compartment and immunoglobulin repertoire formation.

Laser transfer for circulating tumor cell isolation in liquid biopsy.

75Cancer research has found in the recent years a formidable ally in liquid biopsy, a noninvasive technique that allows the study of circulating tumor cells (CTCs) and biomolecules involved in the dynamics of cancer spread like cell-free nucleid acids or tumor-derived extracellular vesicles. However, single-cell isolation of CTCs with high viability for further genetic, phenotypic, and morphological characterization remains a challenge. We present a new approach for single CTC isolation in enriched blood samples using a liquid laser transfer (LLT) process, adapted from standard laser direct write techniques. In order to completely preserve the cells from direct laser irradiation, we used an ultraviolet laser to produce a blister-actuated laser-induced forward transfer process (BA-LIFT). Using a plasma-treated polyimide layer for blister generation, we completely shield the sample from the incident laser beam. The optical transparency of the polyimide allows direct cell targeting using a simplified optical setup, in which the laser irradiation module, standard imaging, and fluorescence imaging share a common optical path. Peripheral blood mononuclear cells (PBMCs) were identified by fluorescent markers, while target cancer cells remained unstained. As a proof of concept, we were able to isolate single MDA-MB-231 cancer cells using this negative selection process. Unstained target cells were isolated and culture while their DNA was sent for single-cell sequencing (SCS). Our approach appears to be an effective approach to isolate single CTCs, preserving cell characteristics in terms of cell viability and potential for further SCS.

Natural Killer Cells Improve Cognitive Function and Support to Induce Amyloid Beta Clearance by Functional Recovery of Impaired Microglia in Natural Killer Cell‐treated Alzheimer’s Diseases Mouse Model

AbstractBackgroundDysfunction of microglia that plays a pivotal role in amyloid beta clearance is recognized to be involved in pathological progression of the Alzheimer’s diseases. Natural killer (NK) cells participate in homeostatic immune‐modulation and immune‐surveillance by secreting immune‐boosting signaling molecules. These molecules can serve as cell‐based therapeutics for AD. In this study, we found that the activated NK cells eliminated Aβ plaques, resulting in a marked improvement in behavior in mice with AD. This improvement may be associated with the recovery in microglial function due to the upregulation of phagocytic activity and autophagy genes.MethodNK cells were isolated, using a negative selection process, from the spleens of BALB/c mice and subsequently expanded to 1×108 cells.ResultThe cultured NK cells were intravenously administered into APP/PS1 mutant mice. There was dramatic reduction of Aβ deposition in the cortex and dentate gyrus areas of the brain in these mice following the NK cell treatment. While phosphate‐buffered saline APP/PS1 control mice exhibited learning deficits in the escape platform, the NK cell‐treated mice showed reduced escape latency in the Morris water maze test. Mouse microglia, in the AD model, were isolated using CD11b positive magnetic activated cell sorting method. RNA sequencing was performed using total RNA isolated from mouse brain hippocampus tissue, to explore differential gene expression levels. Hierarchical cluster heat maps revealed the recovered gene populations in the NK‐treated microglial group. The percentage of genes upregulated in the total gene ontology groups were significantly altered in NK treated/sham ratio group (i.e., 171 upregulated immune response‐related genes). The homeostatic and disease‐associated microglia (DAM)‐related genes that were increased in microglia isolated from APP/PS1 mouse brain were downregulated after NK treatment. KEGG pathway analysis projected the autophagy signaling pathways as critical pathways associated with amyloid beta clearance. Our analysis showed that treatment of mice with NK cells recovered gene signatures involved in phagocytic activity.ConclusionThese findings show that NK cells, which are known to have low in vivo toxicity, could be a potential therapeutic option for AD that could be rapidly translated to the clinic.

Isolation of Murine Articular Chondrocytes for Single-Cell RNA or Bulk RNA Sequencing Analysis.

Single-cell RNA sequencing (scRNA-seq) is highly dependent on cellular composition of a tissue of interest. For soft tissues, isolation of individual cells from the extracellular matrix (ECM) while retaining viability and minimizing degradation within subpopulations is well established. In contrast, articular cartilage is comprised of sparsely positioned chondrocytes embedded within a dense ECM high in glycosaminoglycans, proteoglycans, and many fibrous proteins such as collagens, elastin, fibronectin, and laminins. This densely packed ECM makes it difficult to isolate viable chondrocytes for further single-cell analysis. This protocol highlights a successful technique optimized for isolating chondrocytes from the articulated joints of rodent animal models using a series of enzymatic digestions and chondrocyte enrichment using a double negative selection process through florescence-activated cell sorting (FACS).

Władza, mięso i Polska Ludowa. O filmie „Wieczne pretensje” Grzegorza Królikiewicza

This article is devoted to Permanent Objections (1975) by Grzegorz Królikiewicz’s second feature film. Using archival materials and the filmmakers’ recollections, the author recalls the context in which the film was made and its reception. In his work, Grzegorz Królikiewicz showed the phenomena characteristic of People’s Republic of Poland: the process of negative selection, humiliation of human dignity, and the creation of power structures based on the master-slave relationship. Important in the construction of Permanent Objections is the slaughterhouse – a metaphor for the processes of functioning in People’s Poland and a reflection on what work, its essence, became in the People’s Republic of Poland. The price for this uncompromising commentary on reality was the marginalization of Permanent Objections only three screen copies were made) and the „censorship” of Grzegorz Królikiewicz, who has functioned on the margins of Polish cinematography ever since.

Abstract 862: Negative cellular outcomes following acute in vivo Vhl inactivation in mice

Abstract Clear cell renal cell carcinoma (ccRCC) is driven by the biallelic inactivation of the von Hippel Lindau tumor suppressor (VHL) gene, which results directly in the normoxic stabilization of hypoxia inducible factors (HIF-1 and -2). While VHL is expressed ubiquitously, its inactivation is tumorigenic only in specific tissues. We hypothesize that this tissue-specificity arises from a negative selective pressure on VHL KO cells that is tolerated in certain contexts. To assess this phenomenon, we induced Vhl deletion in vivo simultaneously across the mouse body and observed cell fate with single-cell resolution. Here we show that inducing widespread inter-organ Vhl deletion results in a massive removal of affected cells from tissue. Our study required technology that allowed us to visualize and isolate Vhl-recombined cells from tissue. For this, we developed a novel lineage marking model in which Cre-mediated excision of Vhl is coupled to knock-in of a tdTomato reporter cassette under the endogenous Vhl promoter. We used this model in conjunction with the ubiquitously-expressed UBC-CreERT2 to induce marked biallelic (KO/KO) or monoallelic (wt/KO) inactivation of Vhl. One week after inactivation was induced by administration of tamoxifen, there were equal numbers of tdTomato-positive cells in both genotypes, implying that initial recombination was similar and that Vhl KO did not affect immediate cell survival. Surprisingly, there was a massive reduction in the number of tdTomato-positive cells in multiple KO/KO organs after four weeks. This loss was accompanied by proliferation of tdTomato-negative cells, as assayed by BrdU incorporation, suggesting that tissues can at least partially compensate for loss of Vhl-inactivated cells. Finally, we found that the removal of cells was preceded by signs of cellular damage and stress, such as accumulation of p27, cytoplasmic translocation of HMGB1, and TUNEL-positivity in the kidney and liver. Taken together, we conclude that Vhl inactivation is inherently deleterious to cells and entrains a negative cell selection process in multiple organs. One corollary is that there must exist some conditions under which such selection might not occur; secondary mutations found in ccRCC, such as in Pbrm1, or loss of individual HIF isoforms, might provide such conditions to Vhl KO cells. Currently we are investigating the role of these additional perturbations in modifying the cellular response to Vhl loss. Our study will provide new insights into the genesis of ccRCC by redefining the mechanisms underlying the creation of pro-tumorigenic niches following Vhl inactivation. Citation Format: Samvid Kurlekar, Joanna D C Lima, Chris W. Pugh, Julie Adam, Peter J. Ratcliffe. Negative cellular outcomes following acute in vivo Vhl inactivation in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 862.

Ultra-rare and common genetic variant analysis converge to implicate negative selection and neuronal processes in the aetiology of schizophrenia

Both common and rare genetic variants (minor allele frequency >1% and <0.1% respectively) have been implicated in the aetiology of schizophrenia. In this study, we integrate single-cell gene expression data with publicly available Genome-Wide Association Study (GWAS) and exome sequenced data in order to investigate in parallel, the enrichment of common and (ultra-)rare variants related to schizophrenia in several functionally relevant gene-sets. Four types of gene-sets were constructed 1) protein-truncating variant (PTV)-intolerant (PI) genes 2) genes expressed in brain cell types and neurons ascertained from mouse and human brain tissue 3) genes defined by synaptic function and location and 4) intersection genes, i.e., PI genes that are expressed in the human and mouse brain cell gene-sets. We show that common as well as ultra-rare schizophrenia-associated variants are overrepresented in PI genes, in excitatory neurons from the prefrontal cortex and hippocampus, medium spiny neurons, and genes enriched for synaptic processes. We also observed stronger enrichment in the intersection genes. Our findings suggest that across the allele frequency spectrum, genes and genetic variants likely to be under stringent selection, and those expressed in particular brain cell types, are involved in the same biological pathways influencing the risk for schizophrenia.

Editing T cell repertoire by thymic epithelial cell-directed gene transfer abrogates risk of type 1 diabetes development

Insulin is the primary autoantigen (Ag) targeted by T cells in type 1 diabetes (T1D). Although biomarkers precisely identifying subjects at high risk of T1D are available, successful prophylaxis is still an unmet need. Leaky central tolerance to insulin may be partially ascribed to the instability of the MHC-InsB9-23 complex, which lowers TCR avidity, thus resulting in defective negative selection of autoreactive clones and inadequate insulin-specific T regulatory cell (Treg) induction. We developed a lentiviral vector (LV)-based strategy to engineer thymic epithelial cells (TECs) to correct diabetogenic T cell repertoire. Intrathymic (it) LV injection established stable transgene expression in EpCAM+ TECs, by virtue of transduction of TEC precursors. it-LV-driven presentation of the immunodominant portion of ovalbumin allowed persistent and complete negative selection of responsive T cells in OT-II chimeric mice. We successfully applied this strategy to correct the diabetogenic repertoire of young non-obese diabetic mice, imposing the presentation by TECs of the stronger agonist InsulinB9-23R22E and partially depleting the existing T cell compartment. We further circumscribed LV-driven presentation of InsulinB9-23R22E by micro-RNA regulation to CD45− TECs without loss of efficacy in protection from diabetes, associated with expanded insulin-specific Tregs. Overall, our gene transfer-based prophylaxis fine-tuned the central tolerance processes of negative selection and Treg induction, correcting an autoimmune prone T cell repertoire.

Regulation of thymic T regulatory cell differentiation by TECs in health and disease

The thymus produces self-limiting and self-tolerant T cells through the interaction between thymocytes and thymus epithelial cells (TECs), thereby generating central immune tolerance. The TECs are composed of cortical and medullary thymic epithelial cells, which regulate the positive and negative selection of T cells, respectively. During the process of negative selection, thymocytes with self-reactive ability are deleted or differentiated into regulatory T cells (Tregs). Tregs are a subset of suppressor T cells that are important for maintaining immune homeostasis. The differentiation and development of Tregs depend on the development of TECs and other underlying molecular mechanisms. Tregs regulated by thymic epithelial cells are closely related to human health and are significant in autoimmune diseases, thymoma and pregnancy. In this review, we summarize the current molecular and transcriptional regulatory mechanisms by which TECs affect the development and function of thymic Tregs. We also review the pathophysiological models of thymic epithelial cells regulating thymic Tregs in human diseases and specific physiological conditions.

Is T Cell Negative Selection a Learning Algorithm?

Our immune system can destroy most cells in our body, an ability that needs to be tightly controlled. To prevent autoimmunity, the thymic medulla exposes developing T cells to normal “self” peptides and prevents any responders from entering the bloodstream. However, a substantial number of self-reactive T cells nevertheless reaches the periphery, implying that T cells do not encounter all self peptides during this negative selection process. It is unclear if T cells can still discriminate foreign peptides from self peptides they haven’t encountered during negative selection. We use an “artificial immune system”—a machine learning model of the T cell repertoire—to investigate how negative selection could alter the recognition of self peptides that are absent from the thymus. Our model reveals a surprising new role for T cell cross-reactivity in this context: moderate T cell cross-reactivity should skew the post-selection repertoire towards peptides that differ systematically from self. Moreover, even some self-like foreign peptides can be distinguished provided that the peptides presented in the thymus are not too similar to each other. Thus, our model predicts that negative selection on a well-chosen subset of self peptides would generate a repertoire that tolerates even “unseen” self peptides better than foreign peptides. This effect would resemble a “generalization” process as it is found in learning systems. We discuss potential experimental approaches to test our theory.

Immunobiology: on the inexistence of a negative selection process

Immunobiology: on the inexistence of a negative selection process

Transforming Growth Factor-beta signaling in \u03b1\u03b2 thymocytes promotes negative selection

In the thymus, the T lymphocyte repertoire is purged of a substantial portion of highly self-reactive cells. This negative selection process relies on the strength of TCR-signaling in response to self-peptide-MHC complexes, both in the cortex and medulla regions. However, whether cytokine-signaling contributes to negative selection remains unclear. Here, we report that, in the absence of Transforming Growth Factor beta (TGF-β) signaling in thymocytes, negative selection is significantly impaired. Highly autoreactive thymocytes first escape cortical negative selection and acquire a Th1-like-phenotype. They express high levels of CXCR3, aberrantly accumulate at the cortico-medullary junction and subsequently fail to sustain AIRE expression in the medulla, escaping medullary negative selection. Highly autoreactive thymocytes undergo an atypical maturation program, substantially accumulate in the periphery and induce multiple organ-autoimmune-lesions. Thus, these findings reveal TGF-β in thymocytes as crucial for negative selection with implications for understanding T cell self-tolerance mechanisms.

Negative selection of MIPs to create high specificity ligands for glycated haemoglobin

The solid-phase imprinting method was used to prepare particles imprinted against glycated haemoglobin by using the whole protein as a template. Obtained MIPs were then treated through a negative selection process to obtain high affinity MIPs able to recognize glycated haemoglobin but without any cross-reactivity towards non-glycated haemoglobin. Both, bulk and selected particles were tested in competitive pseudo-ELISA assays with haemoglobin and glycated haemoglobin as free targets. In both cases, a linear response was observed from 10−3 nM to 1 nM. After negative selection, MIPs showed no response to non-glycated haemoglobin together with an improved of the linear range of the assay. It also allowed quantification of glycated haemoglobin in human serum with recoveries above 95%.

NSNAD: negative selection-based network anomaly detection approach with relevant feature subset

Intrusion detection systems are one of the security tools widely deployed in network architectures in order to monitor, detect and eventually respond to any suspicious activity in the network. However, the constantly growing complexity of networks and the virulence of new attacks require more adaptive approaches for optimal responses. In this work, we propose a semi-supervised approach for network anomaly detection inspired from the biological negative selection process. Based on a reduced dataset with a filter/ranking feature selection technique, our algorithm, namely negative selection for network anomaly detection (NSNAD), generates a set of detectors and uses them to classify events as anomaly. Otherwise, they are matched against an Artificial Human Leukocyte Antigen in order to be classified as normal. The accuracy and the computational time of NSNAD are tested under three intrusion detection datasets: NSL-KDD, Kyoto2006+ and UNSW-NB15. We compare the performance of NSNAD against a fully supervised algorithm (Naive Bayes), an unsupervised clustering algorithm (K-means) and a semi-supervised algorithm (One-class SVM) with respect to multiple accuracy metrics. We also compare the time incurred by each algorithm in training and classification stages.

Fairtrade credentialism: towards understanding certified producer organizations’ perceptions of Fairtrade as a credential

ABSTRACTFairtrade is a transnational voluntary labelling initiative that aims to upgrade the social, economic, and environmental conditions of producers in developing countries. In this paper, we systematically translated, coded, and analysed open-ended responses from a global survey of Fairtrade producers to explore how Fairtrade operates as a credential. The credentialism literature sheds light on Fairtrade's ability to create social and economic mobility, the operation of positive and negative selection processes and the hidden curriculum. We conclude with research and policy recommendations, including the need for the research community and Fairtrade International to track and monitor initial conditions of Fairtrade producers and measure progress over time to improve understanding of how Fairtrade operates as a credential and structures the social and economic mobility of developing country producers.

Characterization of adiponectin‐expressing cells in thymus

ObjectiveAdiponectin, a protein considered as the most abundant adipokine, was found to be expressed in the thymus of wild type mice. The present study characterized the identity and function of adiponectin‐expressing cells in thymus.MethodsThymus was collected from mice with (WT) or without (AKO) adiponectin for isolation and enrichment of thymic nurse cell complexes (TNCs). Different populations of lymphocytes were analyzed by flow cytometry and confocal microscopy. Protein expressions were evaluated by immunofluorescence staining and/or Western blotting.ResultsAdiponectin‐expressing cells were present in TNCs, the specific epithelial cell complexes which engulf thymocytes and provide microenvironment for T lymphocyte development. Compared with age‐matched WT mice, the number and size of TNCs in thymus of AKO mice were significantly reduced. The percentage composition of CD3+ double positive (DP) lymphocytes was significantly decreased, whereas the total amount of double negative (DN) thymocytes significantly increased in TNCs of AKO mice. Adiponectin‐expressing cells were derived from a subpopulation of early T progenitors, which facilitated the formation and function of TNCs. Treatment with adiponectin in vivo or ex vivo could promote the formation and functions of TNCs.ConclusionsAdiponectin‐expressing cells play important roles in the positive and negative selection process of TNCs, thus regulating T‐cell maturation and development in thymus. The results have important implications on the anti‐inflammatory, anti‐diabetic and anti‐tumorigenic properties of adiponectin.Support or Funding InformationThis work was supported in part by grants from Seeding Funds for basic research of the University of Hong Kong, Research Council Grants (17153016) and Hong Kong Health and Medical Research Fund (04151796), Collaborative Research Fund of Hong Kong (C7055‐14G) and the National Basic Research Program of China (973 Program 2015CB553603).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.