Explore the vast range of titles available.

Bacterial binding to host receptors underlies both commensalism and pathogenesis. Many streptococci adhere to protein-attached carbohydrates expressed on cell surfaces using Siglec-like binding regions (SLBRs). The precise glycan repertoire recognized may dictate whether the organism is a strict commensal versus a pathogen. However, it is currently not clear what drives receptor selectivity. Here, we use five representative SLBRs and identify regions of the receptor binding site that are hypervariable in sequence and structure. We show that these regions control the identity of the preferred carbohydrate ligand using chimeragenesis and single amino acid substitutions. We further evaluate how the identity of the preferred ligand affects the interaction with glycoprotein receptors in human saliva and plasma samples. As point mutations can change the preferred human receptor, these studies suggest how streptococci may adapt to changes in the environmental glycan repertoire. Streptococcal siglec-like binding regions (SLBRs) selectively bind cell surface glycans, but the basis for this selectivity is not understood. Here, the authors identify selectivity-modulating SLBR regions and study how changes in SLBR glycan selectivity affect interactions with human glycoprotein receptors.

Tropical pulmonary eosinophilia (TPE) is a chronic respiratory syndrome associated with Lymphatic Filariasis (LF), a tropical parasitic infection of the human, transmitted by mosquitoes. The larval form of LF (microfilariae) are trapped in the lungs of TPE subjects have a major role in initiating the TPE syndrome. To date, there are no reports on the potential allergen that is responsible for generating parasite-specific IgE in TPE. In this project, we screened a cDNA expression library of the microfilarial stages of Wuchereria bancrofti with monoclonal IgE antibodies prepared from subjects with clinical filarial infections. Our studies identified a novel molecule that showed significant sequence similarity to an allergen. A blast analysis showed the presence of similar proteins in a number of nematodes parasites. Thus, we named this molecule as Nematode Pan Allergen (NPA). Subsequent functional analysis showed that NPA is a potent allergen that can cause release of histamine from mast cells, induce secretion of proinflammatory cytokines from alveolar macrophages and promote accumulation of eosinophils in the tissue, all of which occur in TPE lungs. Based on our results, we conclude that the NPA protein secreted by the microfilariae of W. bancrofti may play a significant role in the pathology of TPE syndrome in LF infected individuals. Further studies on this molecule can help design an approach to neutralize the NPA in an attempt to reduce the pathology associated with TPE in LF infected subjects.

BackgroundRenal cell carcinoma (RCC) is a prevalent and aggressive form of kidney cancer, with variable response rates to checkpoint blockade immunotherapies. While high T cell infiltration often indicates a favorable response to immunotherapies, this correlation is inconsistent in RCC. To accurately identify RCC patients who will benefit from immunotherapies, additional markers are needed to differentiate between subsets of tumor-infiltrating T cells. Recent advances in single-cell sequencing and subcellular spatial transcriptomics have revolutionized cancer immunology, enabling the analysis of individual cells and their interactions within the tumor microenvironment.MethodsIn this study, we used comprehensively analyzed the molecular profiles of individual cells in RCC to understand the interplay between tumor cells and neighboring immune cells. Utilizing patient-matched peripheral blood mononuclear cells, cryopreserved dissociated tumor, and adjacent normal cells, we performed single-cell RNA, antibody-derived tag, and TCR sequencing on the blood and dissociated cells (n=10 patients). 10x Genomics Xenium in situ spatial transcriptomics with single-cell resolution was conducted using a custom designed gene panel targeting kidney, tumor specific genes and various immune related genes with emphasis on those relevant to the analysis of T cells, which was guided by single-cell RNA sequencing data. Formalin-fixed paraffin-embedded samples from tumor and adjacent normal tissue were subjected to in situ spatial transcriptomics (n=4 patients).ResultsBy aligning single-cell RNA sequencing and in situ spatial transcriptomics with single-cell level resolution, our findings revealed highly heterogeneous yet distinct T cell subpopulations within renal cell tumors compared to adjacent normal tissues. Notably, tumor-infiltrating CD8 and CD4 T cells expressing CXCL13, which is often associated with T cell exhaustion program, demonstrated a highly organized spatial distribution. These cells were positioned in close proximity to tumor cells, suggesting antigen-specific engagement. Furthermore, we tracked corresponding T cell subsets and clones in patient-matched blood samples, assessing their phenotypes as potential biomarkers for tumor-reactive T cells.ConclusionsThrough the integration of single-cell multi-omics analyses and single-cell in situ spatial transcriptomics, we addressed critical questions concerning tumor heterogeneity, spatial organization, and the dynamic interplay between cancer cells and their microenvironment in RCC. These advancements hold promise for the development of improved therapeutic strategies, enhancing the effectiveness of cancer treatments and facilitating patient stratification for checkpoint blockade immunotherapy.AcknowledgementsThis project was supported by funding from an IIRC post-doctoral fellowship (to HR), a post-doctoral training fellowship from the National Research Foundation of Korea (to HR), and Aldarra foundation (to EN).Ethics ApprovalThe samples were provided by Northwest BioSpecimen and the analysis was performed according to the IRB file/approval number IR File #10422.

Colony-stimulating factor 1 (CSF1) and interleukin 34 (IL34) signal the CSF1 receptor to regulate macrophage differentiation. Studies in IL34- or CSF1-deficient mice have revealed that IL34 function is limited to the central nervous system and skin during development. However, the roles of IL34 and CSF1 at homeostasis or in the context of inflammatory diseases or cancer in wild-type mice have not been clarified . By neutralizing CSF1 and/or IL34 in adult mice, we identified that they play important roles in macrophage differentiation, specifically in steady-state microglia, Langerhans cells, and kidney macrophages. In several inflammatory models, neutralization of both CSF1 and IL34 contributed to maximal disease protection. However, in a myeloid cell-rich tumor model, CSF1 but not IL34 was required for tumor-associated macrophage accumulation and immune homeostasis. Analysis of human inflammatory conditions reveals IL34 upregulation that may account for the protection requirement of IL34 blockade. Furthermore, evaluation of IL34 and CSF1 blockade treatment during infection reveals no substantial safety concerns. Thus, IL34 and CSF1 play non-redundant roles in macrophage differentiation, and therapeutic intervention targeting IL34 and/or CSF1 may provide an effective treatment in macrophage-driven immune-pathologies.

Human leukocyte antigen (HLA) gene is a highly polymorphic region. HLA typing is required to match patients and donors for transplantation; therefore, development of HLA registries is necessary for finding HLA match donors. HLA system is highly informative, and numerous studies have been conducted on HLA allele distribution in different populations. In this study, 100 unrelated Iranian individuals were typed for HLA-A locus using sequence-based typing method. Samples were subjected to the PCR, followed by Sanger sequencing and software analysis. A*02:01 (13%) and A*24:02 (12%) were the two most frequent alleles, while A*01:14, A*02:05, A*02:11, A*02:34, A*02:50, A*11:04, A*23:02, A*24:34, A*25:01, A*26:09, A*26:43, A*29:67, A*30:54, A*31:02, A*31:66, A*32:03, A*32:04, A*33:03, and A*66:15 alleles had the least frequencies (1%). This is the first report of HLA-A allele level typing in a randomized population of Iran and can be useful for development of national registries of HLA-typed volunteer marrow donors and local cord blood banks.

Single-cell spatial transcriptomics promises a highly detailed view of a cell's transcriptional state and microenvironment, yet inaccurate cell segmentation can render this data murky by misattributing large numbers of transcripts to nearby cells or conjuring nonexistent cells. We adopt methods from ab initio cell simulation to rapidly infer morphologically plausible cell boundaries that preserve cell type heterogeneity. Benchmarking applied to datasets generated by three commercial platforms show superior performance and computational efficiency of this approach compared with existing methods. We show that improved accuracy in cell segmentation aids greatly in detection of difficult to accurately segment tumor infiltrating immune cells such as neutrophils and T cells. Lastly, through improvements in our ability to delineate subsets of tumor infiltrating T cells, we show that CXCL13-expressing CD8+ T cells tend to be more closely associated with tumor cells than their CXCL13-negative counterparts in data generated from renal cell carcinoma patient samples.

Tropical pulmonary eosinophilia (TPE) is a chronic respiratory syndrome associated with Lymphatic Filariasis (LF), a tropical parasitic infection of the human, transmitted by mosquitoes. A larval form of LF, the microfilariae trapped in the lungs of TPE subjects have a major role in initiating the TPE syndrome. To date, there are no reports on the potential allergen that is responsible for generating parasite-specific IgE in TPE. In this project, we screened a cDNA expression library of the microfilarial stages of Wuchereria bancrofti with monoclonal IgE antibodies prepared from subjects with clinical filarial infections. Our studies identified a novel molecule that showed significant sequence similarity to an allergen. A blast analysis showed the presence of similar proteins in a number of nematodes parasites. Thus, we named the molecule as Nematode Pan Allergen (NPA). Subsequent functional analysis showed that NPA is a potent allergen that can cause release of histamine from mast cells, induce secretion of proinflammatory cytokines from alveolar macrophages and promote accumulation of eosinophils, all of which occur in TPE lungs. Therefore, we believe that NPA may have a significant role in the pathology of the TPE syndrome.Competing Interest StatementThe authors have declared no competing interest.

The Siglec-like Serine-Rich Repeat (SRR) adhesins mediate bacterial attachment to mammalian hosts via sialoglycan receptors. Here, we combine structural, computational, biochemical, and phylogenetic approaches to elucidate the determinants of the sialoglycan-binding spectrum across the family of Siglec-like SRR adhesins. We further identified mutable positions that disproportionately affect sialoglycan selectivity, as demonstrated by increases in binding to alternative ligands of 2- to 3- orders of magnitude. Biologically, these studies highlight how bacteria nimbly modulate the receptor interaction during coevolution of host and pathogen. These studies additionally created binding proteins specific for sialyl-T antigen or 6S-sialyl LewisX that can recognize glycosylation of human plasma proteins. The engineered binding proteins can facilitate the characterization of normal cellular glycan modifications or may be used as diagnostic tools in disease states with altered glycosylation.