Emergence and fate of stem cell-like Tcf7+ CD8+ T cells during a primary immune response to viral infection

In response to infection, naïve CD8+ T (TN) cells yield a large pool of short-lived terminal effector (TTE) cells that eliminate infected host cells. In parallel, a minor population of stem cell-like central memory (TCM) cells forms, which has the capacity to maintain immunity after pathogen clearance. It has remained uncertain whether stem-like TCM cells arise by dedifferentiation from a subset of cytolytic TTE cells or whether priming generates stem-like cells capable of seeding the TCM compartment and, if so, when cytolytic TTE cells branch off. Here, we show that CD8+ T cells with stem-like properties, which are identified by the expression of TCF1 (encoded by Tcf7), are present across the primary response to infection. Priming programs TN cells to undergo multiple cell divisions, over the course of which TCF1 expression is maintained. These TCF1+ cells further expand relatively independently of systemic inflammation, antigen dose, or affinity, and they quantitatively yield TCF1+ TCM cells after pathogen clearance. Inflammatory signals suppress TCF1 expression in early divided TCF1+ cells. TCF1 down-regulation is associated with the irreversible loss of self-renewal capacity and the silencing of stem/memory genes, which precedes the stable acquisition of a TTE state. TCF1 expression restrains cell cycling, explaining in part the limited expansion of TCF1+ relative to TCF1- cells during the primary response. Thus, our data are consistent with terminal differentiation of effector cells being a step-wise process that is initiated by inflammation in primed stem-like cells, which would otherwise become central memory cells by default.

Activation of the transcription factor NFAT5 in the tumor microenvironment enforces CD8+ T cell exhaustion

Persistent exposure to antigen during chronic infection or cancer renders T cells dysfunctional. The molecular mechanisms regulating this state of exhaustion are thought to be common in infection and cancer, despite obvious differences in their microenvironments. Here we found that NFAT5, an NFAT family transcription factor that lacks an AP-1 docking site, was highly expressed in exhausted CD8+ T cells in the context of chronic infections and tumors but was selectively required in tumor-induced CD8+ T cell exhaustion. Overexpression of NFAT5 in CD8+ T cells reduced tumor control, while deletion of NFAT5 improved tumor control by promoting the accumulation of tumor-specific CD8+ T cells that had reduced expression of the exhaustion-associated proteins TOX and PD-1 and produced more cytokines, such as IFNɣ and TNF, than cells with wild-type levels of NFAT5, specifically in the precursor exhausted PD-1+TCF1+TIM-3-CD8+ T cell population. NFAT5 did not promote T cell exhaustion during chronic infection with clone 13 of lymphocytic choriomeningitis virus. Expression of NFAT5 was induced by TCR triggering, but its transcriptional activity was specific to the tumor microenvironment and required hyperosmolarity. Thus, NFAT5 promoted the exhaustion of CD8+ T cells in a tumor-selective fashion.

Dynamic single-cell regulomes characterize human peripheral blood innate lymphoid cell subpopulations

Innate lymphoid cells (ILCs) are plastic immune cells divided into 3 main subsets, characterized by distinct phenotypic and functional profiles. Using single cell approaches, heightened heterogeneity of mouse ILCs has been appreciated, imprinted by tissue signals that shape their transcriptome and epigenome. Intra-subset diversity has also been observed in human ILCs. However, combined transcriptomic and epigenetic analyses of single ILCs in humans are lacking. Here, we show high transcriptional and epigenetic heterogeneity among human circulating ILCs in healthy individuals. We describe phenotypically distinct subclusters and diverse chromatin accessibility within main ILC populations, compatible with differentially poised states. We validate the use of this healthy donor-based analysis as resource dataset to help inferring ILC changes occurring in disease conditions. Overall, our work provides insights in the complex human ILC biology. We anticipate it to facilitate hypothesis-driven studies in patients, without the need to perform single cell OMICs using precious patients' material.

Reductive carboxylation epigenetically instructs T cell differentiation

Protective immunity against pathogens or cancer is mediated by the activation and clonal expansion of antigen-specific naive T cells into effector T cells. To sustain their rapid proliferation and effector functions, naive T cells switch their quiescent metabolism to an anabolic metabolism through increased levels of aerobic glycolysis, but also through mitochondrial metabolism and oxidative phosphorylation, generating energy and signalling molecules1-3. However, how that metabolic rewiring drives and defines the differentiation of T cells remains unclear. Here we show that proliferating effector CD8+ T cells reductively carboxylate glutamine through the mitochondrial enzyme isocitrate dehydrogenase 2 (IDH2). Notably, deletion of the gene encoding IDH2 does not impair the proliferation of T cells nor their effector function, but promotes the differentiation of memory CD8+ T cells. Accordingly, inhibiting IDH2 during ex vivo manufacturing of chimeric antigen receptor (CAR) T cells induces features of memory T cells and enhances antitumour activity in melanoma, leukaemia and multiple myeloma. Mechanistically, inhibition of IDH2 activates compensating metabolic pathways that cause a disequilibrium in metabolites regulating histone-modifying enzymes, and this maintains chromatin accessibility at genes that are required for the differentiation of memory T cells. These findings show that reductive carboxylation in CD8+ T cells is dispensable for their effector response and proliferation, but that it mainly produces a pattern of metabolites that epigenetically locks CD8+ T cells into a terminal effector differentiation program. Blocking this metabolic route allows the increased formation of memory T cells, which could be exploited to optimize the therapeutic efficacy of CAR T cells.

Assessment of the Cardiac Noncoding Transcriptome by Single-Cell RNA Sequencing Identifies FIXER, a Conserved Profibrogenic Long Noncoding RNA

BACKGROUND

Cardiac fibroblasts have crucial roles in the heart. In particular, fibroblasts differentiate into myofibroblasts in the damaged myocardium, contributing to scar formation and interstitial fibrosis. Fibrosis is associated with heart dysfunction and failure. Myofibroblasts therefore represent attractive therapeutic targets. However, the lack of myofibroblast-specific markers has precluded the development of targeted therapies. In this context, most of the noncoding genome is transcribed into long noncoding RNAs (lncRNAs). A number of lncRNAs have pivotal functions in the cardiovascular system. lncRNAs are globally more cell-specific than protein-coding genes, supporting their importance as key determinants of cell identity.

METHODS

In this study, we evaluated the value of the lncRNA transcriptome in very deep single-cell RNA sequencing. We profiled the lncRNA transcriptome in cardiac nonmyocyte cells after infarction and probed heterogeneity in the fibroblast and myofibroblast populations. In addition, we searched for subpopulation-specific markers that can constitute novel targets in therapy for heart disease.

RESULTS

We demonstrated that cardiac cell identity can be defined by the sole expression of lncRNAs in single-cell experiments. In this analysis, we identified lncRNAs enriched in relevant myofibroblast subpopulations. Selecting 1 candidate we named FIXER (fibrogenic LOX-locus enhancer RNA), we showed that its silencing limits fibrosis and improves heart function after infarction. Mechanitically, FIXER interacts with CBX4, an E3 SUMO protein ligase and transcription factor, guiding CBX4 to the promoter of the transcription factor RUNX1 to control its expression and, consequently, the expression of a fibrogenic gene program.. FIXER is conserved in humans, supporting its translational value.

CONCLUSIONS

Our results demonstrated that lncRNA expression is sufficient to identify the various cell types composing the mammalian heart. Focusing on cardiac fibroblasts and their derivatives, we identified lncRNAs uniquely expressed in myofibroblasts. In particular, the lncRNA FIXER represents a novel therapeutic target for cardiac fibrosis.

Endothelial cell-derived oxysterol ablation attenuates experimental autoimmune encephalomyelitis

The vasculature is a key regulator of leukocyte trafficking into the central nervous system (CNS) during inflammatory diseases including multiple sclerosis (MS). However, the impact of endothelial-derived factors on CNS immune responses remains unknown. Bioactive lipids, in particular oxysterols downstream of Cholesterol-25-hydroxylase (Ch25h), promote neuroinflammation but their functions in the CNS are not well-understood. Using floxed-reporter Ch25h knock-in mice, we trace Ch25h expression to CNS endothelial cells (ECs) and myeloid cells and demonstrate that Ch25h ablation specifically from ECs attenuates experimental autoimmune encephalomyelitis (EAE). Mechanistically, inflamed Ch25h-deficient CNS ECs display altered lipid metabolism favoring polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) expansion, which suppresses encephalitogenic T lymphocyte proliferation. Additionally, endothelial Ch25h-deficiency combined with immature neutrophil mobilization into the blood circulation nearly completely protects mice from EAE. Our findings reveal a central role for CNS endothelial Ch25h in promoting neuroinflammation by inhibiting the expansion of immunosuppressive myeloid cell populations.

Longitudinal analysis of DC subsets in patients with ovarian cancer: Implications for immunotherapy

Background

The use of circulating cDC1 to generate anti-cancer vaccines is among the most promising approaches to overcome the limited immunogenicity and clinical efficacy of monocyte-derived DC. However, the recurrent lymphopenia and the reduction of DC numbers and functionality in patients with cancer may represent an important limitation of such approach. In patients with ovarian cancer (OvC) that had received chemotherapy, we previously showed that cDC1 frequency and function were reduced.

Methods

We recruited healthy donors (HD, n=7) and patients with OvC at diagnosis and undergoing interval debulking surgery (IDS, n=6), primary debulking surgery (PDS, n=6) or at relapse (n=8). We characterized longitudinally phenotypic and functional properties of peripheral DC subsets by multiparametric flow cytometry.

Results

We show that the frequency of cDC1 and the total CD141+ DC capacity to take up antigen are not reduced at the diagnosis, while their TLR3 responsiveness is partially impaired in comparison with HD. Chemotherapy causes cDC1 depletion and increase in cDC2 frequency, but mainly in patients belonging to the PDS group, while in the IDS group both total lymphocytes and cDC1 are preserved. The capacity of total CD141+ DC and cDC2 to take up antigen is not impacted by chemotherapy, while the activation capacity upon Poly(I:C) (TLR3L) stimulation is further decreased.

Conclusions

Our study provides new information about the impact of chemotherapy on the immune system of patients with OvC and sheds a new light on the importance of considering timing with respect to chemotherapy when designing new vaccination strategies that aim at withdrawing or targeting specific DC subsets.

c-MAF coordinates enterocyte zonation and nutrient uptake transcriptional programs

Small intestinal villi are structural and functional units present in higher vertebrates and uniquely adapted to nutrient absorption. Villus enterocytes are organized in transcriptional "zones" dedicated to specialized tasks such as absorption of specific nutrients. We report that the transcription factor c-MAF is expressed in differentiated lower and mid-villus enterocytes and is a target of BMP signaling. Maf inactivation perturbed the villus zonation program by increasing carbohydrate-related transcripts while suppressing transcripts linked to amino-acid and lipid absorption. The formation of cytoplasmic lipid droplets, shuttling dietary fat to chylomicrons, was impaired upon Maf loss indicating its role in dietary lipid handling. Maf inactivation under homeostatic conditions expanded tuft cells and led to compensatory gut lengthening, preventing weight loss. However, delayed Maf-/- enterocyte maturation impaired weight recovery after acute intestinal injury, resulting in reduced survival. Our results identify c-MAF as a regulator of the intestinal villus zonation program, while highlighting the importance of coordination between stem/progenitor and differentiation programs for intestinal regeneration.

Integrated multi-omics reveals cellular and molecular interactions governing the invasive niche of basal cell carcinoma

Tumors invade the surrounding tissues to progress, but the heterogeneity of cell types at the tumor-stroma interface and the complexity of their potential interactions hampered mechanistic insight required for efficient therapeutic targeting. Here, combining single-cell and spatial transcriptomics on human basal cell carcinomas, we define the cellular contributors of tumor progression. In the invasive niche, tumor cells exhibit a collective migration phenotype, characterized by the expression of cell-cell junction complexes. In physical proximity, we identify cancer-associated fibroblasts with extracellular matrix-remodeling features. Tumor cells strongly express the cytokine Activin A, and increased Activin A-induced gene signature is found in adjacent cancer-associated fibroblast subpopulations. Altogether, our data identify the cell populations and their transcriptional reprogramming contributing to the spatial organization of the basal cell carcinoma invasive niche. They also demonstrate the power of integrated spatial and single-cell multi-omics to decipher cancer-specific invasive properties and develop targeted therapies.

The role of reciprocal tumour-stroma interactions in tumour invasion remains poorly characterised. Here, single-cell and spatial transcriptomics identifies the cell populations and their transcriptional reprogramming contributing to the spatial organization of the basal cell carcinoma invasive niche.

Gliadin-reactive vitamin D-sensitive proinflammatory ILCPs are enriched in celiac patients

Celiac disease (CD) is a multisystem disease in which different organs may be affected. We investigate whether circulating innate lymphoid cells (ILCs) contribute to the CD peripheral inflammatory status. We find that the CD cytokine profile is characterized by high concentrations of IL-12p40, IL-18, and IFN-γ, paralleled by an expansion of ILC precursors (ILCPs). In the presence of the gliadin peptides p31-43 and pα-9, ILCPs from CD patients increase transglutaminase 2 (TG2) expression, produce IL-18 and IFN-γ, and stimulate CD4⁺ T lymphocytes. IFN-γ is also produced upon stimulation with IL-12p40 and IL-18 and is inhibited by the addition of vitamin D. Low levels of blood vitamin D correlate with high IFN-γ and ILCP presence and mark the CD population mostly affected by extraintestinal symptoms. Dietary vitamin D supplementation appears to be an interesting therapeutic approach to dampen ILCP-mediated IFN-γ production.

The mitochondrial pyruvate carrier regulates memory T cell differentiation and antitumor function

Glycolysis, including both lactate fermentation and pyruvate oxidation, orchestrates CD8⁺ T cell differentiation. However, how mitochondrial pyruvate metabolism and uptake controlled by the mitochondrial pyruvate carrier (MPC) impact T cell function and fate remains elusive. We found that genetic deletion of MPC drives CD8⁺ T cell differentiation toward a memory phenotype. Metabolic flexibility induced by MPC inhibition facilitated acetyl-coenzyme-A production by glutamine and fatty acid oxidation that results in enhanced histone acetylation and chromatin accessibility on pro-memory genes. However, in the tumor microenvironment, MPC is essential for sustaining lactate oxidation to support CD8⁺ T cell antitumor function. We further revealed that chimeric antigen receptor (CAR) T cell manufacturing with an MPC inhibitor imprinted a memory phenotype and demonstrated that infusing MPC inhibitor-conditioned CAR T cells resulted in superior and long-lasting antitumor activity. Altogether, we uncover that mitochondrial pyruvate uptake instructs metabolic flexibility for guiding T cell differentiation and antitumor responses.

c-Maf enforces cytokine production and promotes memory-like responses in mouse and human type 2 innate lymphoid cells

Group‐2 innate lymphoid cells (ILC2s), which are involved in type 2 inflammatory diseases such as allergy, can exhibit immunological memory, but the basis of this ILC2 "trained immunity" has remained unclear. Here, we found that stimulation with IL‐33/IL‐25 or exposure to the allergen papain induces the expression of the transcription factor c‐Maf in mouse ILC2s. Chronic papain exposure results in high production of IL‐5 and IL‐13 cytokines and lung eosinophil recruitment, effects that are blocked by c‐Maf deletion in ILCs. Transcriptomic analysis revealed that knockdown of c‐Maf in ILC2s suppresses expression of type 2 cytokine genes, as well as of genes linked to a memory‐like phenotype. Consistently, c‐Maf was found highly expressed in human adult ILC2s but absent in cord blood and required for cytokine production in isolated human ILC2s. Furthermore, c‐Maf‐deficient mouse or human ILC2s failed to exhibit strengthened (“trained”) responses upon repeated challenge. Thus, the expression of c‐Maf is indispensable for optimal type 2 cytokine production and proper memory‐like responses in group‐2 innate lymphoid cells.

Loss of vascular endothelial notch signaling promotes spontaneous formation of tertiary lymphoid structures

Tertiary lymphoid structures (TLS) are lymph node-like immune cell clusters that emerge during chronic inflammation in non-lymphoid organs like the kidney, but their origin remains not well understood. Here we show, using conditional deletion strategies of the canonical Notch signaling mediator Rbpj, that loss of endothelial Notch signaling in adult mice induces the spontaneous formation of bona fide TLS in the kidney, liver and lung, based on molecular, cellular and structural criteria. These TLS form in a stereotypical manner around parenchymal arteries, while secondary lymphoid structures remained largely unchanged. This effect is mediated by endothelium of blood vessels, but not lymphatics, since a lymphatic endothelial-specific targeting strategy did not result in TLS formation, and involves loss of arterial specification and concomitant acquisition of a high endothelial cell phenotype, as shown by transcriptional analysis of kidney endothelial cells. This indicates a so far unrecognized role for vascular endothelial cells and Notch signaling in TLS initiation.

Loss of canonical Notch signaling in vascular endothelial cells induces spontaneous formation of proto-typical tertiary lymphoid structures in mouse kidney, liver and lungs, which form around central arteries that acquire a high endothelial cell signature

PD-1+ Tcf1+ CD8+ T cells from established chronic infection can form memory while retaining a stableimprint of persistent antigen exposure

Virus-specific PD1+ Tcf1+ memory-like CD8+ T cells (TMLs) maintain the CD8+ T cell response during chronic viral infection. However, the fate of these cells following cessation of persistent antigen exposure has been unclear. Here, we find that TMLs persist upon transfer into antigen-free hosts and form memory following recall stimulation. Phenotypic, functional, and transcriptome analyses show that TML-derived memory cells resemble those arising in response to acute, resolved infection, but they retain features of chronically stimulated cells, including elevated PD-1 and Tox and reduced cytokine expression. This chronic infection imprint is largely accounted for by constitutive Tox expression. Virus-specific Tcf1+ CD8+ T cells that persist after clearance of systemic infection also display a chronic infection imprint. Notwithstanding, renewed virus exposure induces a recall response, which controls virus infection in part. Thus, cessation of chronic antigen exposure yields a memory CD8+ T cell compartment that reflects prior stimulation.

Characterization of the blood-brain barrier in genetically diverse laboratory mouse strains

Background

Genetic variation in a population has an influence on the manifestation of monogenic as well as multifactorial disorders, with the underlying genetic contribution dependent on several interacting variants. Common laboratory mouse strains used for modelling human disease lack the genetic variability of the human population. Therefore, outcomes of rodent studies show limited relevance to human disease. The functionality of brain vasculature is an important modifier of brain diseases. Importantly, the restrictive interface between blood and brain—the blood–brain barrier (BBB) serves as a major obstacle for the drug delivery into the central nervous system (CNS). Using genetically diverse mouse strains, we aimed to investigate the phenotypic and transcriptomic variation of the healthy BBB in different inbred mouse strains.

Methods

We investigated the heterogeneity of brain vasculature in recently wild-derived mouse strains (CAST/EiJ, WSB/EiJ, PWK/PhJ) and long-inbred mouse strains (129S1/SvImJ, A/J, C57BL/6J, DBA/2J, NOD/ShiLtJ) using different phenotypic arms. We used immunohistochemistry and confocal laser microscopy followed by quantitative image analysis to determine vascular density and pericyte coverage in two brain regions—cortex and hippocampus. Using a low molecular weight fluorescence tracer, sodium fluorescein and spectrophotometry analysis, we assessed BBB permeability in young and aged mice of selected strains. For further phenotypic characterization of endothelial cells in inbred mouse strains, we performed bulk RNA sequencing of sorted endothelial cells isolated from cortex and hippocampus.

Results

Cortical vessel density and pericyte coverage did not differ among the investigated strains, except in the cortex, where PWK/PhJ showed lower vessel density compared to NOD/ShiLtJ, and a higher pericyte coverage than DBA/2J. The vascular density in the hippocampus differed among analyzed strains but not the pericyte coverage. The staining patterns of endothelial arteriovenous zonation markers were similar in different strains. BBB permeability to a small fluorescent tracer, sodium fluorescein, was also similar in different strains, except in the hippocampus where the CAST/EiJ showed higher permeability than NOD/ShiLtJ. Transcriptomic analysis of endothelial cells revealed that sex of the animal was a major determinant of gene expression differences. In addition, the expression level of several genes implicated in endothelial function and BBB biology differed between wild-derived and long-inbred mouse strains. In aged mice of three investigated strains (DBA/2J, A/J, C57BL/6J) vascular density and pericyte coverage did not change—expect for DBA/2J, whereas vascular permeability to sodium fluorescein increased in all three strains.

Conclusions

Our analysis shows that although there were no major differences in parenchymal vascular morphology and paracellular BBB permeability for small molecular weight tracer between investigated mouse strains or sexes, transcriptomic differences of brain endothelial cells point to variation in gene expression of the intact BBB. These baseline variances might be confounding factors in pathological conditions that may lead to a differential functional outcome dependent on the sex or genetic polymorphism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-021-00269-w.

PPARɣ drives IL-33-dependent ILC2 pro-tumoral functions

Group 2 innate lymphoid cells (ILC2s) play a critical role in protection against helminths and in diverse inflammatory diseases by responding to soluble factors such as the alarmin IL-33, that is often overexpressed in cancer. Nonetheless, regulatory factors that dictate ILC2 functions remain poorly studied. Here, we show that peroxisome proliferator-activated receptor gamma (PPARγ) is selectively expressed in ILC2s in humans and in mice, acting as a central functional regulator. Pharmacologic inhibition or genetic deletion of PPARγ in ILC2s significantly impair IL-33-induced Type-2 cytokine production and mitochondrial fitness. Further, PPARγ blockade in ILC2s disrupts their pro-tumoral effect induced by IL-33-secreting cancer cells. Lastly, genetic ablation of PPARγ in ILC2s significantly suppresses tumor growth in vivo. Our findings highlight a crucial role for PPARγ in supporting the IL-33 dependent pro-tumorigenic role of ILC2s and suggest that PPARγ can be considered as a druggable pathway in ILC2s to inhibit their effector functions. Hence, PPARγ targeting might be exploited in cancer immunotherapy and in other ILC2-driven mediated disorders, such as asthma and allergy.

CD40 Agonist Targeted to Fibroblast Activation Protein α Synergizes with Radiotherapy in Murine HPV-Positive Head and Neck Tumors

PURPOSE

The incidence of human papillomavirus-associated head and neck squamous cell carcinoma (HPV⁺-HNSCC) is rising worldwide and although current therapeutic modalities are efficient in the majority of patients, there is a high rate of treatment failures. Thus, novel combination approaches are urgently needed to achieve better disease control in patients with HPV⁺-HNSCC. We investigated the safety and therapeutic efficacy of a novel fibroblast activation protein (FAP)-targeted CD40 agonist (FAP-CD40) in combination with local hypofractionated radiation in a syngeneic HPV⁺-HNSCC model.

EXPERIMENTAL DESIGN

Using an established orthotopic model, we treated tumor-bearing mice with local hypofractionated radiotherapy (2 × 6 Gy) alone or in combination with a systemic administration of the FAP-CD40 antibody. Following up the mice, we evaluated the changes in the tumor microenvironment (TME) by immunofluorescence, FACS, and NanoString RNA analysis.

RESULTS

The suboptimal radiotherapy regimen chosen failed to control tumors in the treated mice. The FAP-CD40 administered in monotherapy transiently controlled tumor growth, whereas the combined therapy induced durable complete responses in more than 80% of the tumor-bearing mice. This notable efficacy relied on the radiotherapy-induced remodeling of the TME and activation of the CD8⁺ T-cell-cDC1 axis and was devoid of the systemic toxicity frequently associated with CD40-targeted therapy. Moreover, the robust immunologic memory developed effectively prevented tumor relapses, a common feature in patients with HNSCC.

CONCLUSIONS

Our study provides proof of concept, as well as mechanistic insights of the therapeutic efficacy of a bispecific FAP-CD40 combined with local radiotherapy in a FAP⁺-HNSCC model increasing overall survival and inducing long-term antitumor immunity.

Blood-brain barrier alterations in human brain tumors revealed by genome-wide transcriptomic profiling

BACKGROUND

Brain tumors, whether primary or secondary, have limited therapeutic options despite advances in understanding driver gene mutations and heterogeneity within tumor cells. The cellular and molecular composition of brain tumor stroma, an important modifier of tumor growth, has been less investigated to date. Only few studies have focused on the vasculature of human brain tumors despite the fact that the blood-brain barrier (BBB) represents the major obstacle for efficient drug delivery.

METHODS

In this study, we employed RNA sequencing to characterize transcriptional alterations of endothelial cells isolated from primary and secondary human brain tumors. We used an immunoprecipitation approach to enrich for endothelial cells from normal brain, glioblastoma (GBM) and lung cancer brain metastasis (BM).

RESULTS

Analysis of the endothelial transcriptome showed deregulation of genes implicated in cell proliferation, angiogenesis and deposition of extracellular matrix (ECM) in the vasculature of GBM and BM. Deregulation of genes defining the BBB dysfunction module were found in both tumor types. We identified deregulated expression of genes in vessel-associated fibroblasts in GBM.

CONCLUSION

We characterize alterations in BBB genes in GBM and BM vasculature and identify proteins that might be exploited for developing drug delivery platforms. In addition, our analysis on vessel-associated fibroblasts in GBM shows that the cellular composition of brain tumor stroma merits further investigation.

Tumor-specific cytolytic CD4 T cells mediate immunity against human cancer

CD4 T cells have been implicated in cancer immunity for their helper functions. Moreover, their direct cytotoxic potential has been shown in some patients with cancer. Here, by mining single-cell RNA-seq datasets, we identified CD4 T cell clusters displaying cytotoxic phenotypes in different human cancers, resembling CD8 T cell profiles. Using the peptide-MHCII-multimer technology, we confirmed ex vivo the presence of cytolytic tumor-specific CD4 T cells. We performed an integrated phenotypic and functional characterization of these cells, down to the single-cell level, through a high-throughput nanobiochip consisting of massive arrays of picowells and machine learning. We demonstrated a direct, contact-, and granzyme-dependent cytotoxic activity against tumors, with delayed kinetics compared to classical cytotoxic lymphocytes. Last, we found that this cytotoxic activity was in part dependent on SLAMF7. Agonistic engagement of SLAMF7 enhanced cytotoxicity of tumor-specific CD4 T cells, suggesting that targeting these cells might prove synergistic with other cancer immunotherapies.

Quantitative and qualitative impairments in dendritic cell subsets of patients with ovarian or prostate cancer

BACKGROUND

Dendritic cells (DCs) are the most efficient antigen-presenting cells, hence initiating a potent and cancer-specific immune response. This ability (mainly using monocyte-derived DCs) has been exploited in vaccination strategies for decades with limited clinical efficacy. Another alternative would be the use of conventional DCs (cDCs) of which at least three subsets circulate in human blood: cDC1s (CD141^bright), cDC2s (CD1c⁺) and plasmacytoid DCs. Despite their paucity, technical advances may allow for their selection and clinical use. However, many assumptions concerning the DC subset biology depend on observations from mouse models, hindering their translational potential. In this study, we characterise human DCs in patients with ovarian cancer (OvC) or prostate cancer (PrC).

PATIENTS AND METHODS

Whole blood samples from patients with OvC or PrC and healthy donors (HDs) were evaluated by flow cytometry for the phenotypic and functional characterisation of DC subsets.

RESULTS

In both patient groups, the frequency of total CD141⁺ DCs was lower than that in HDs, but the cDC1 subset was only reduced in patients with OvC. CD141⁺ DCs showed a reduced response to the TLR3 agonist poly (I:C) in both groups of patients. An inverse correlation between the frequency of cDC1s and CA125, the OvC tumour burden marker, was observed. Consistently, high expression of CLEC9A in OvC tissue (The Cancer Genome Atlas data set) indicated a better overall survival.

CONCLUSIONS

cDC1s are reduced in patients with OvC, and CD141⁺ DCs are quantitatively and qualitatively impaired in patients with OvC or PrC. CD141⁺ DC activation may predict functional impairment. The loss of cDC1s may be a bad prognostic factor for patients with OvC.

Distinct and shared gene expression for human innate versus adaptive helper lymphoid cells

Innate lymphoid cells (ILCs) are the latest identified innate immune cell family. Given their similarity in transcription factor expression and cytokine secretion profiles, ILCs have been considered as the innate phenocopy of CD4 Th cells. Here, we explored the transcriptome of circulating human ILC subsets as opposed to CD4 Th cell subsets. We describe transcriptomic differences between total ILCs and total CD4 Th cells, as well as between paired innate and adaptive cell subsets (ILC1 vs. Th1; ILC2 vs. Th2; and ILC3 vs. Th17 cells). In particular, we observed differences in expression of genes involved in cell trafficking such as CCR1, CCR6 and CXCR3, innate activation and inhibitory functions, including CD119, 2B4, TIGIT, and CTLA‐4, and neuropeptide receptors, such as VIPR2. Moreover, we report for the first time on distinct expression of long noncoding RNAs (lncRNAs) in innate vs. adaptive cells, arguing for a potential role of lncRNA in shaping human ILC biology. Altogether, our results point for unique, rather than redundant gene organization in ILCs compared to CD4 Th cells, in regard to kinetics, fine‐tuning and spatial organization of the immune response.

Investigating unexplained genetic variation and its expression in the arbuscular mycorrhizal fungus Rhizophagus irregularis: A comparison of whole genome and RAD sequencing data

Arbuscular mycorrhizal fungi (AMF) are important symbionts of plants. Recently, studies of the AMF Rhizophagus irregularis recorded within-isolate genetic variation that does not completely match the proposed homokaryon or heterokaryon state (where heterokaryons comprise a population of two distinct nucleus genotypes). We re-analysed published data showing that bi-allelic sites (and their frequencies), detected in proposed homo- and heterokaryote R. irregularis isolates, were similar across independent studies using different techniques. This indicated that observed within-fungus genetic variation was not an artefact of sequencing and that such within- fungus genetic variation possibly exists. We then looked to see if bi-allelic transcripts from three R. irregularis isolates matched those observed in the genome as this would give a strong indication of whether bi-allelic sites recorded in the genome were reliable variants. In putative homokaryon isolates, very few bi-allelic transcripts matched those in the genome. In a putative heterokaryon, a large number of bi-allelic transcripts matched those in the genome. Bi-allelic transcripts also occurred in the same frequency in the putative heterokaryon as predicted from allele frequency in the genome. Our results indicate that while within-fungus genome variation in putative homokaryon and heterokaryon AMF was highly similar in 2 independent studies, there was little support that this variation is transcribed in homokaryons. In contrast, within-fungus variation thought to be segregated among two nucleus genotypes in a heterokaryon isolate was indeed transcribed in a way that is proportional to that seen in the genome.

Associations between digit ratio (2D4D), mood, and autonomic stress response in healthy men

The ratio between the length of the second (index) and the fourth (ring) finger (2D4D) is a putative biomarker of prenatal testosterone (T) exposure, with higher exposure leading to a smaller ratio. 2D4D has further been linked to mental and somatic disorders. Healthy male Swiss recruits (N = 245; M_age = 20.30 years) underwent a psychosocial stress test. Mood and salivary alpha-amylase (sAA) were assessed before and after the stress test, while heart rate (HR) and heart rate variability (HRV) were measured continuously. Additionally, 2D4D (right: R2D4D; left: L2D4D) was determined and divided into quartile groups. Correlation analysis showed no associations between R/L2D4D and outcome measures. Comparing calculated quartiles for R2D4D, subjects in the lowest R2D4D quartile expressed trendwise (p < 0.10) lower positive and higher negative affect, significantly elevated sAA activity (p < 0.05), but no HR and HRV differences at baseline as compared to subjects in the upper three quartiles. With regard to acute stress, subjects in the lowest as compared to subjects in the upper three R2D4D quartiles showed a higher increase of negative affect and a stronger cardiac response (p < 0.05), but no alterations in positive affect and sAA activity. Young healthy men in the lowest R2D4D quartile revealed a more negative affect and increased physiological activity at baseline and in response to acute stress. An exposure to high levels of prenatal T might constitute a risk factor potentially increasing vulnerability to stress-related disorders in men.

Variation in allele frequencies at the bg112 locus reveals unequal inheritance of nuclei in a dikaryotic isolate of the fungus Rhizophagus irregularis

The genetic state of the arbuscular mycorrhizal fungus species Rhizophagus irregularis differs among isolates, including both homokaryotic and dikaryotic isolates. Via the production of multi-nucleate axexual spores, siblings of dikaryotic isolates may inherit unequal frequencies of nucleotypes. Using bg112, a microsatellite marker, previous studies revealed that lines deriving from single spores of the dikaryotic R. irregularis isolate C3 differed in their proportions of different alleles. A genomic study of single nuclei of R. irregularis, however, suggested that this marker was a multi-copy locus and that therefore it was inappropriate to study the inheritance of nuclei in dikaryotic isolates. In this study, we first analysed whole genome data of several R. irregularis isolates and demonstrated that bg112 is indeed a single copy locus in these genomes. Thus, the bg112 locus is a suitable marker to study the relative frequency of nucleotypes in R. irregularis. Second, by using amplicon sequencing, we confirmed the existence of one allele of bg112 in two homokaryotic isolates (DAOM197198 and C2) and two alleles in the dikaryotic isolate (C3). Finally, we found that the relative proportions of two bg112 alleles differed significantly among dikaryotic single-spore lines derived from isolate C3, indicating that genetically different nucleotypes are inherited unequally in this dikaryotic R. irregularis isolate.

A population genomics approach shows widespread geographical distribution of cryptic genomic forms of the symbiotic fungus Rhizophagus irregularis

Arbuscular mycorrhizal fungi (AMF; phylum Gomeromycota) associate with plants forming one of the most successful microbe-plant associations. The fungi promote plant diversity and have a potentially important role in global agriculture. Plant growth depends on both inter- and intra-specific variation in AMF. It was recently reported that an unusually large number of AMF taxa have an intercontinental distribution, suggesting long-distance gene flow for many AMF species, facilitated by either long-distance natural dispersal mechanisms or human-assisted dispersal. However, the intercontinental distribution of AMF species has been questioned because the use of very low-resolution markers may be unsuitable to detect genetic differences among geographically separated AMF, as seen with some other fungi. This has been untestable because of the lack of population genomic data, with high resolution, for any AMF taxa. Here we use phylogenetics and population genomics to test for intra-specific variation in Rhizophagus irregularis, an AMF species for which genome sequence information already exists. We used ddRAD sequencing to obtain thousands of markers distributed across the genomes of 81 R. irregularis isolates and related species. Based on 6 888 variable positions, we observed significant genetic divergence into four main genetic groups within R. irregularis, highlighting that previous studies have not captured underlying genetic variation. Despite considerable genetic divergence, surprisingly, the variation could not be explained by geographical origin, thus also supporting the hypothesis for at least one AMF species of widely dispersed AMF genotypes at an intercontinental scale. Such information is crucial for understanding AMF ecology, and how these fungi can be used in an environmentally safe way in distant locations.

L-dopa Modulates Striatal Functional Connectivity in Adults with Psychotic-like Experiences: A Randomized Double-blind Placebo-controlled Study

Introduction

According to the dopamine hypothesis functional brain abnormalities and neurochemical alterations may converge to cause psychosis through aberrant salience attribution. Indeed, resting-state functional magnetic resonance imaging (rs-fMRI) has revealed widespread brain disconnectivity across the psychotic spectrum.

Objectives

To advance the understanding of the dopaminergic involvement in intrinsic functional connectivity (iFC) and its putative relationship to the development of psychotic disorders we aimed to investigate the link between L-Dopa, a dopamine precursor, and its modulation of striatal iFC in subthreshold psychosis, i.e. non-clinical psychosis.

Methods

We used a randomized, double-blind placebo controlled study design including in our sample 56 healthy, male, right-handed, subjects with no familiar risk factors for psychosis who were assessed with the Schizotypal Personality Questionnaire (SPQ) and underwent 10 minutes of rs-fMRI scanning. All subjects received either 250 mg of Madopar DR®(200 mg L-Dopa plus 50 mg benserazid, dual release form) or a placebo. We analysed resting-state iFC of 6 striatal seeds, known to evoke dopamine related networks.

Results

The main effect of L-Dopa presented itself (FWE-corrected) as a significant decrease in iFC from the right ventral striatum to the cerebellum and the precuneus cortex, and an increase in iFC to the occipital cortex. Subjects with high SPQ positive symptom sub-scores showed a significant increase of L-Dopa induced connectivity.

Conclusion

We identified striatal functional connectivity being modulated by augmented dopamine availability, and in support of the dopamine hypothesis, we found that those iFC patterns are associated to high scores of psychotic like experiences.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Population genomics reveals that within-fungus polymorphism is common and maintained in populations of the mycorrhizal fungus Rhizophagus irregularis

Arbuscular mycorrhizal (AM) fungi are symbionts of most plants, increasing plant growth and diversity. The model AM fungus Rhizophagus irregularis (isolate DAOM 197198) exhibits low within-fungus polymorphism. In contrast, another study reported high within-fungus variability. Experiments with other R. irregularis isolates suggest that within-fungus genetic variation can affect the fungal phenotype and plant growth, highlighting the biological importance of such variation. We investigated whether there is evidence of differing levels of within-fungus polymorphism in an R. irregularis population. We genotyped 20 isolates using restriction site-associated DNA sequencing and developed novel approaches for characterizing polymorphism among haploid nuclei. All isolates exhibited higher within-isolate poly-allelic single-nucleotide polymorphism (SNP) densities than DAOM 197198 in repeated and non-repeated sites mapped to the reference genome. Poly-allelic SNPs were independently confirmed. Allele frequencies within isolates deviated from diploids or tetraploids, or that expected for a strict dikaryote. Phylogeny based on poly-allelic sites was robust and mirrored the standard phylogeny. This indicates that within-fungus genetic variation is maintained in AM fungal populations. Our results predict a heterokaryotic state in the population, considerable differences in copy number variation among isolates and divergence among the copies, or aneuploidy in some isolates. The variation may be a combination of all of these hypotheses. Within-isolate genetic variation in R. irregularis leads to large differences in plant growth. Therefore, characterizing genomic variation within AM fungal populations is of major ecological importance.

Trunk muscle strength tests to predict injuries, attrition and military ability in soldiers

AIM

Physical fitness is related to injuries, attrition and military ability in military organisations. Therefore, all military organizations of the North Atlantic Treaty Organizations (NATO) test their employees' physical fitness at least once a year. The sit-up test is part of most of the fitness test batteries used. A possible alternative to the sit-up test is the global trunk muscle strength test (TMS). The aim of the present study was to compare the predictability of injuries, attrition and military ability between TMS and sit-up test performances.

METHODS

A total of 230 male recruits in a Swiss Army fusilier company completed TMS and sit-up tests in week 1 of military training school. During the following 13 weeks, injuries, attrition and military ability data were collected. Statistical analysis included backward binary regression and receiver operating characteristic (ROC) curve analysis to compare the discriminative power of TMS and the sit-up test to predict injuries, attrition and military ability.

RESULTS

ROC analysis revealed larger areas under the curve for total injuries, attrition and military ability for the TMS (areatotal injuries=0.58; areaattrition=0.60; areamilitary ability=0.59) than for the sit-up test (areatotal injuries=0.53; areaattrition=0.50; areamilitary ability=0.56). Binary logistic regression analysis revealed low body mass index, low TMS performance and cigarette smoking to be potential risk factors for injuries; while sit-up performance was extracted from the model.

CONCLUSION

The TMS seems to be a valid alternative to the sit-up test in a military setting due to its appropriate results in predicting injuries in the present study.

Comparative analysis of genome sequences from four strains of the Buchnera aphidicola Mp endosymbion of the green peach aphid, Myzus persicae

BACKGROUND

Myzus persicae, the green peach aphid, is a polyphagous herbivore that feeds from hundreds of species of mostly dicot crop plants. Like other phloem-feeding aphids, M. persicae rely on the endosymbiotic bacterium, Buchnera aphidicola (Buchnera Mp), for biosynthesis of essential amino acids and other nutrients that are not sufficiently abundant in their phloem sap diet. Tobacco-specialized M. persicae are typically red and somewhat distinct from other lineages of this species. To determine whether the endosymbiotic bacteria of M. persicae could play a role in tobacco adaptation, we sequenced the Buchnera Mp genomes from two tobacco-adapted and two non-tobacco M. persicae lineages.

RESULTS

With a genome size of 643.5 kb and 579 predicted genes, Buchnera Mp is the largest Buchnera genome sequenced to date. No differences in gene content were found between the four sequenced Buchnera Mp strains. Compared to Buchnera APS from the well-studied pea aphid, Acyrthosiphon pisum, Buchnera Mp has 21 additional genes. These include genes encoding five enzymes required for biosynthesis of the modified nucleoside queosine, the heme pathway enzyme uroporphyrinogen III synthase, and asparaginase. Asparaginase, which is also encoded by the genome of the aphid host, may allow Buchnera Mp to synthesize essential amino acids from asparagine, a relatively abundant phloem amino acid.

CONCLUSIONS

Together our results indicate that the obligate intracellular symbiont Buchnera aphidicola does not contribute to the adaptation of Myzus persicae to feeding on tobacco.

A comparative study of exceptional experiences of clients seeking advice and of subjects in an ordinary population

Exceptional experiences (EE) occur frequently within the populations of many countries and across various socio-cultural contexts. Although some EE show similarities with mental disorders, it would be a mistake to identify them in general as disorders. In fact, the vast number of individuals reporting EE includes subclinical and completely healthy subjects. We conducted a comparative empirical study of several characteristics of EE for two samples - one from ordinary population and the other from clients seeking advice. We found surprisingly similar phenomenological patterns of EE in both samples, but the frequency and intensity of EE for clients seeking advice significantly exceeded those for the ordinary population. Our results support the hypothesis of a continuous spectrum between mental health and mental disorder for the types of experiences analyzed.

The Swiss Army physical fitness test battery predicts risk of overuse injuries among recruits

AIM

The aim of this study was to quantify the discriminative power of physical performance tests to recognize conscripts with enhanced risk of acute and overuse injuries in specific, physically demanding occupational specialties of the Swiss Army. The five performance tests investigated represent the Swiss Army Physical Fitness Test Battery.

METHODS

Physical fitness performances were assessed during recruitment procedures prior to military service, and injury occurrences were assessed during 18 weeks of boot camp. Complete fitness and injury data of 459 volunteers from four military occupational specialties were collected. Discriminative power of volunteers' aerobic endurance capacity, trunk muscle fitness, muscle power of upper and lower extremities, and balance for predicting risk of acute injuries and for predicting risk of overuse injuries was calculated using receiver operating characteristic curve analysis.

RESULTS

The presented fitness tests had no discriminative power for predicting the risk of acute injuries. However, the trunk muscle fitness test was discriminative in predicting overuse injuries in all four military occupational specialties, progressive endurance run in three, balance test in two, and standing long jump in one. Only the seated shot put had no significant power for predicting overuse injuries in all four study groups. However, for different occupational specialties, different fitness parameters were discriminative to predict overuse injuries.

CONCLUSION

It is possible to conclude that the fitness tests used allow detection of conscripts with enhanced overuse injury risk in physically demanding occupational specialties and therefore provide an indicator to select suitable personnel for physically demanding jobs in a military organization.

Green evolution and dynamic adaptations revealed by genomes of the marine picoeukaryotes Micromonas

Picoeukaryotes are a taxonomically diverse group of organisms less than 2 micrometers in diameter. Photosynthetic marine picoeukaryotes in the genus Micromonas thrive in ecosystems ranging from tropical to polar and could serve as sentinel organisms for biogeochemical fluxes of modern oceans during climate change. These broadly distributed primary producers belong to an anciently diverged sister clade to land plants. Although Micromonas isolates have high 18S ribosomal RNA gene identity, we found that genomes from two isolates shared only 90% of their predicted genes. Their independent evolutionary paths were emphasized by distinct riboswitch arrangements as well as the discovery of intronic repeat elements in one isolate, and in metagenomic data, but not in other genomes. Divergence appears to have been facilitated by selection and acquisition processes that actively shape the repertoire of genes that are mutually exclusive between the two isolates differently than the core genes. Analyses of the Micromonas genomes offer valuable insights into ecological differentiation and the dynamic nature of early plant evolution.

[Significance of axial rotation alignment of components of knee prostheses]

Increased internal malrotation of the tibial and femoral components affects kinematics of the patellofemoral joint and the flexion gap. A combined tibial and femoral malrotation may lead to maltracking of the patella. Isolated internal malrotation of the femoral component results in an asymmetric flexion gap. Clinically, the patients suffer from either lateral instability or medial stiffness in flexion. Lateral flexion instability leads to medial tibial pain,difficulties standing up from a chair,or instability during descending stairs or walking downhill. Medial stiffness in flexion may lead to secondary arthrofibrosis. There are three methods for determining femoral rotation by bony landmarks: (1) posterior condyles with 3 degrees of external rotation, (2) anterior-posterior axis according to Whiteside, and (3) transepicondylar axis. The transepicondylar axis approximates the flexion axis of the knee. All three bony landmarks have the disadvantage that they will not create a symmetric flexion gap in all cases. The balanced flexion gap technique seeks to achieve a perfectly balanced extension gap first, and then aligns the femoral component parallel to the tibial resection plane when the knee is under symmetric distraction in 90 degrees of flexion. The soft tissue releases for varus or valgus contraction have to be performed in extension first until the mechanical axis passes through the center of the knee, the center of the femoral head, and the center of the ankle. Using these methods, both,extension and flexion gap will become rectangular. The balanced flexion gap method has the disadvantage that the femoral component will not be aligned parallel to the epicondylar axis in some cases. It is not known which of the two methods will produce better clinical results. Rotational positioning of the tibial component referenced on the tibial tuberosity represents the most reliable method. Placing the tibial component according to the femoral component using the floating technique may increase an internal malrotation problem of the femur if present.

[Combined deficiency of thyroid stimulating hormone and growth hormone in a diabetic patient with Hashimoto thyroiditis]

We report the case of a 36-year-old female patient with insulin dependent diabetes who developed hypothyroidism of pituitary origin after giving birth. She had low levels of free T4 and TSH with no response to i.v. TRH. Antimicrosome antibodies were increased (1/25000), suggesting Hashimoto's thyroiditis. The other hormones were normal except for a low level of growth hormone and insulin growth factor 1. There were no antibodies against the pituitary. MRI of the pituitary was normal. We suspect a vascular origin for this partial pituitary deficiency.

Endothelium-independent relaxation and hyperpolarization to C-type natriuretic peptide in porcine coronary arteries

Endothelial cells produce C-type natriuretic peptide (CNP), which has been proposed as an endothelium-derived hyperpolarizing factor. In porcine coronary arteries, we investigated the vasodilatory effects of CNP and compared them with endothelium-dependent relaxations and hyperpolarizations to bradykinin. Isolated epicardial porcine coronary arteries were studied in organ chambers, and concentration-response curves to CNP and bradykinin were obtained. Membrane potential was measured in endothelial cells and smooth muscle of intact porcine coronary arteries during stimulation with CNP or bradykinin. In precontracted porcine coronary arteries with or without endothelium, CNP (10[-10]-10[-6] M) evoked relaxations (maximum, 42 +/- 4%) smaller than those evoked by bradykinin (100 +/- 1%), blunted in preparations contracted by KCl instead of U46619 (9,11-dideoxy-11a,9a-epoxymethano-prostaglandin F2alpha; p < 0.05) and unaffected by inhibition of NO synthase (NS). CNP evoked hyperpolarization of vascular smooth muscle of similar magnitude in endothelium-intact (-4.4 +/- 1 mV) and endothelium-denuded (-4.6 +/- 1 mV) porcine coronary arteries. Bradykinin (10[-10]-10[-6] M) evoked concentration-dependent relaxations in preparations with endothelium only. Although atrial natriuretic peptide-receptor antagonist HS-142-1 (25 microM) slightly reduced the sensitivity to bradykinin (log shift at IC50, twofold; p < 0.05), it had no effect on the maximal response to bradykinin. Inhibition of NO synthase partially attenuated, whereas high potassium chloride (30 mM) markedly inhibited relaxations to bradykinin (p < 0.05). Hyperpolarization to bradykinin was much more pronounced than that to CNP (-17 +/- 3 mV; p < 0.05 vs. CNP) and was observed in endothelium-intact preparations only and unaffected by HS-142-1. In conclusion, in contrast to bradykinin, CNP induces endothelium-independent and weaker relaxation and hyperpolarization of coronary artery vascular smooth muscle, suggesting that CNP is an unlikely mediator of endothelium-dependent hyperpolarization of porcine coronary arteries.

Dichotomous effect of monocyte Fc receptor interaction on anti-CD3-induced immunoglobulin synthesis

Monoclonal antibodies against the TCR/CD3 complex are capable of activating T cells which in turn may induce immunoglobulin synthesis in B cells under appropriate conditions. Here we present evidence that distinct immune responses, induced by four commonly used TCR/CD3 mAb (Leu4, OKT3, BMA030, BMA031) were related to the mAb interaction with monocyte Fc receptors for IgG. Depending on their isotype and on the technique by which they were crosslinked, TCR/CD3 mAb induced variable IgM and IgG synthesis in PBMC: If the mAb were crosslinked by monocyte IgG-Fc receptors they induced a high Ig production, while crosslinking the same mAb by plastic-bound goat anti-mouse antibodies (panning) failed to do so. Nevertheless, both crosslinking techniques triggered a strong proliferation and IL-2, IL-4, and IFN gamma lymphokine gene expression. The lack of Ig production under panning conditions was due to an additional IgG-Fc receptor interaction with monocytes: (a) If namely mAb F(ab')2 fragments, or mAb isotypes unable to bind to monocyte Fc receptors (IgG2b, IgG1 in nonresponders) were crosslinked by panning, both a good proliferation as well as Ig production ensued; (b) if TCR/CD3 mAb isotypes which could additionally bind to monocyte Fc receptor (IgG2a) were crosslinked, no Ig production occurred; (c) if mAb F(ab')2 fragments were crosslinked with a second anti-T cell antibody of IgG2a isotype, which could bind to monocyte Fc receptors, Ig synthesis was reduced. Interestingly enough, this diminishing effect, due to monocyte Fc receptor interaction, was only observed if CD4-positive cells were proliferating, but not if CD8-positive cells were activated.

Lymphokine gene expression related to CD4 T cell subset (CD45R/CDw29) phenotype conversion

In this study, we investigated whether the phenotype-related differentiation of human 2H4+ (CD45R) naive cells to 2H4- (CDw29) memory CD4 cells corresponded to modulation of interleukin (IL) 2, IL 4, interferon (IFN)-gamma and granulocyte-monocyte colony-stimulating factor (GM-CSF) gene expression, a phenomenon which might correlate to the distinct functional activities of naive cells or memory cells. To mimic in vitro CD4 T cell subset differentiation, freshly isolated 2H4+ and 2H4- CD4 cells were stimulated with the anti-CD3 antibody (Leu-4), expanded in IL 2-containing medium and restimulated with Leu-4 after 7 and 13 days. Absence of monocyte-T cell interaction was compensated by adding monocyte supernatant to the culture medium and by cross-linking the anti-CD3 antibodies with goat anti-mouse antibody coated on culture dishes. It has been previously shown that in vitro stimulated 2H4+ cells acquire CDw29 surface antigens. Measurement of lymphokine gene expression by dot-blot hybridization revealed that although stimulated 2H4+ cells proliferated less than stimulated 2H4- cells, and expressed less actin mRNA, they expressed more IL 2 but less IL 4 and GM-CSF than 2H4- cells. No significant difference was observed between the two subsets for the expression of IFN-gamma. If subsets were restimulated with Leu-4 antibodies, expression of IL 2 was decreased and expression of IL 4 was increased in both subsets; however, the differences among the subsets persisted. They were even more enhanced for IL 2 but less pronounced for GM-CSF. Thus, in spite of phenotype conversion, CD4 T cell subsets maintained a distinct capacity to express IL 2 and IL 4 genes.

Amino acids and lipoproteins in plasma of duodenopancreatectomized patients: effects of glucagon in physiological amounts

Duodenopancreatectomy induces a severe glucagon deficiency and elevated plasma concentrations of alanine, aspartate, glycine, proline, serine, arginine, citrulline, ornithine, phenylalanine and tyrosine. Restoring high physiological plasma glucagon in six such patients by infusing 0.3 mg/24 h of exogenous glucagon reduced significantly (P less than 0.01 or 0.001) the mentioned amino acids (except phenylalanine) and further asparagine, glutamine, methionine and threonine. In six normal subjects the same infusion reduced significantly (P less than 0.05 to 0.001) plasma alanine, asparagine, glutamate, glutamine, glycine, proline, serine, threonine, arginine, ornithine, lysine and tyrosine. However, the effect was significantly (P less than 0.01 or 0.001) less marked for alanine, glutamine, glycine, methionine, serine, threonine and arginine. This particular glucagon sensitivity of duodenopancreatectomized patients suggests that glucagon deficiency is the cause of their hyperaminacidaemia. By contrast, lipoprotein concentrations were virtually unaffected by either glucagon deficiency or its replacement. In the light of the marked hypoaminacidaemia in glucagonoma patients these results attribute to glucagon a major role as a regulator of protein metabolism.

Glucagon immunoreactivities and amino acid profile in plasma of duodenopancreatectomized patients

Glucogon immunoreactivity (IRG) was measured in plasma of duodenopancreatectomized subjects with a nonspecific (K-4023) and a specific (30-K) glucagon antiserum. After an overnight fast, plasma IRG (K-4023) was significantly (P < 0.05) higher in the subjects without pancreas, averaging 782+/-79 (SEM) pgeq/ml, than in the controls (482+/-80 pgeq/ml). IRG (30-K) of 162+/-68 pg/ml did not change during an infusion of arginine (450 mg/kg per 40 min). Insulin deprivation during 3 d in one patient did not restore the IRG response to arginine as reported in depancreatized dogs.Bio-Gel P-30 column chromatography revealed that virtually all IRG (30-K) measured in whole plasma was of different molecular weight than glucagon, and primarily of a mol wt >/= 40,000. Intravenous arginine did not significantly alter the chromatographic pattern of these plasmas. Thus, as postulated by others, duodeno-pancreatectomized humans have virtually no circulating 3,500-dalton glucagon. Hence, the presence of 3,500-dalton glucagon in plasma is not a condition for the diabetic state. It might, nevertheless, when present in normal or excessive amounts, worsen the metabolic state of diabetic patients. Among 14 amino acids measured in plasma of these patients, the concentrations of alanine, serine, ornithine, and arginine were significantly (P < 0.05) elevated to approximately twice that of normal: alanine and serine are both substrates for gluconeogenesis, whereas ornithine and arginine are involved in the formation of urea, the second product of hepatic gluconeogenesis. As the concentrations of branched chain amino acids were not grossly altered, it is hypothesized that this amino acid pattern is a consequence of glucagon deficiency rather than secondary to the diabetic state of these patients.