Unconventional human CD61 pairing with CD103 promotes TCR signaling and antigen-specific T cell cytotoxicity.

Cancer remains one of the leading causes of mortality worldwide, leading to increased interest in utilizing immunotherapy strategies for better cancer treatments. In the past decade, CD103+ T cells have been associated with better clinical prognosis in patients with cancer. However, the specific immune mechanisms contributing toward CD103-mediated protective immunity remain unclear. Here, we show an unexpected and transient CD61 expression, which is paired with CD103 at the synaptic microclusters of T cells. CD61 colocalization with the T cell antigen receptor further modulates downstream T cell antigen receptor signaling, improving antitumor cytotoxicity and promoting physiological control of tumor growth. Clinically, the presence of CD61+ tumor-infiltrating T lymphocytes is associated with improved clinical outcomes, mediated through enhanced effector functions and phenotype with limited evidence of cellular exhaustion. In conclusion, this study identified an unconventional and transient CD61 expression and pairing with CD103 on human immune cells, which potentiates a new target for immune-based cellular therapies.

Follicular regulatory T cells produce neuritin to regulate B cells.

Regulatory T cells prevent the emergence of autoantibodies and excessive IgE, but the precise mechanisms are unclear. Here, we show that BCL6-expressing Tregs, known as follicular regulatory T (Tfr) cells, produce abundant neuritin protein that targets B cells. Mice lacking Tfr cells or neuritin in Foxp3-expressing cells accumulated early plasma cells in germinal centers (GCs) and developed autoantibodies against histones and tissue-specific self-antigens. Upon immunization, these mice also produced increased plasma IgE and IgG1. We show that neuritin is taken up by B cells, causes phosphorylation of numerous proteins, and dampens IgE class switching. Neuritin reduced differentiation of mouse and human GC B cells into plasma cells, downregulated BLIMP-1, and upregulated BCL6. Administration of neuritin to Tfr-deficient mice prevented the accumulation of early plasma cells in GCs. Production of neuritin by Tfr cells emerges as a central mechanism to suppress B cell-driven autoimmunity and IgE-mediated allergies.

COVID-19 Makes B Cells Forget, but T Cells Remember.

Understanding which arms of the immune response are responsible for protection against SARS-CoV-2 infection is key to predicting long-term immunity and to inform vaccine design. Two studies in this issue of Cell collectively suggest that, although SARS-CoV-2 infection may blunt long-lived antibody responses, immune memory might still be achieved through virus-specific memory T cells.

Class-Switch Recombination Occurs Infrequently in Germinal Centers.

Class-switch recombination (CSR) is a DNA recombination process that replaces the immunoglobulin (Ig) constant region for the isotype that can best protect against the pathogen. Dysregulation of CSR can cause self-reactive BCRs and B cell lymphomas; understanding the timing and location of CSR is therefore important. Although CSR commences upon T cell priming, it is generally considered a hallmark of germinal centers (GCs). Here, we have used multiple approaches to show that CSR is triggered prior to differentiation into GC B cells or plasmablasts and is greatly diminished in GCs. Despite finding a small percentage of GC B cells expressing germline transcripts, phylogenetic trees of GC BCRs from secondary lymphoid organs revealed that the vast majority of CSR events occurred prior to the onset of somatic hypermutation. As such, we have demonstrated the existence of IgM-dominated GCs, which are unlikely to occur under the assumption of ongoing switching.

TLR7 gain-of-function genetic variation causes human lupus.

Although circumstantial evidence supports enhanced Toll-like receptor 7 (TLR7) signalling as a mechanism of human systemic autoimmune disease1-7, evidence of lupus-causing TLR7 gene variants is lacking. Here we describe human systemic lupus erythematosus caused by a TLR7 gain-of-function variant. TLR7 is a sensor of viral RNA8,9 and binds to guanosine10-12. We identified a de novo, previously undescribed missense TLR7Y264H variant in a child with severe lupus and additional variants in other patients with lupus. The TLR7Y264H variant selectively increased sensing of guanosine and 2',3'-cGMP10-12, and was sufficient to cause lupus when introduced into mice. We show that enhanced TLR7 signalling drives aberrant survival of B cell receptor (BCR)-activated B cells, and in a cell-intrinsic manner, accumulation of CD11c+ age-associated B cells and germinal centre B cells. Follicular and extrafollicular helper T cells were also increased but these phenotypes were cell-extrinsic. Deficiency of MyD88 (an adaptor protein downstream of TLR7) rescued autoimmunity, aberrant B cell survival, and all cellular and serological phenotypes. Despite prominent spontaneous germinal-centre formation in Tlr7Y264H mice, autoimmunity was not ameliorated by germinal-centre deficiency, suggesting an extrafollicular origin of pathogenic B cells. We establish the importance of TLR7 and guanosine-containing self-ligands for human lupus pathogenesis, which paves the way for therapeutic TLR7 or MyD88 inhibition.

Clathrin mediates both internalization and vesicular release of triggered T cell receptor at the immunological synapse.

Ligation of T cell receptor (TCR) to peptide-MHC (pMHC) complexes initiates signaling leading to T cell activation and TCR ubiquitination. Ubiquitinated TCR is then either internalized by the T cell or released toward the antigen-presenting cell (APC) in extracellular vesicles. How these distinct fates are orchestrated is unknown. Here, we show that clathrin is first recruited to TCR microclusters by HRS and STAM2 to initiate release of TCR in extracellular vesicles through clathrin- and ESCRT-mediated ectocytosis directly from the plasma membrane. Subsequently, EPN1 recruits clathrin to remaining TCR microclusters to enable trans-endocytosis of pMHC-TCR conjugates from the APC. With these results, we demonstrate how clathrin governs bidirectional membrane exchange at the immunological synapse through two topologically opposite processes coordinated by the sequential recruitment of ecto- and endocytic adaptors. This provides a scaffold for direct two-way communication between T cells and APCs.

Circulating galectin-1 delineates response to bevacizumab in melanoma patients and reprograms endothelial cell biology.

Blockade of vascular endothelial growth factor (VEGF) signaling with bevacizumab, a humanized anti-VEGF monoclonal antibody (mAb), or with receptor tyrosine kinase inhibitors, has improved progression-free survival and, in some indications, overall survival across several types of cancers by interrupting tumor angiogenesis. However, the clinical benefit conferred by these therapies is variable, and tumors from treated patients eventually reinitiate growth. Previously we demonstrated, in mouse tumor models, that galectin-1 (Gal1), an endogenous glycan-binding protein, preserves angiogenesis in anti-VEGF-resistant tumors by co-opting the VEGF receptor (VEGFR)2 signaling pathway in the absence of VEGF. However, the relevance of these findings in clinical settings is uncertain. Here, we explored, in a cohort of melanoma patients from AVAST-M, a multicenter, open-label, randomized controlled phase 3 trial of adjuvant bevacizumab versus standard surveillance, the role of circulating plasma Gal1 as part of a compensatory mechanism that orchestrates endothelial cell programs in bevacizumab-treated melanoma patients. We found that increasing Gal1 levels over time in patients in the bevacizumab arm, but not in the observation arm, significantly increased their risks of recurrence and death. Remarkably, plasma Gal1 was functionally active as it was able to reprogram endothelial cell biology, promoting migration, tubulogenesis, and VEGFR2 phosphorylation. These effects were prevented by blockade of Gal1 using a newly developed fully human anti-Gal1 neutralizing mAb. Thus, using samples from a large-scale clinical trial from stage II and III melanoma patients, we validated the clinical relevance of Gal1 as a potential mechanism of resistance to bevacizumab treatment.

Low-grade Chronic Inflammation: A Shared Mechanism for Chronic Diseases.

Inflammation is an important physiological response of the organism to restore homeostasis upon pathogenic or damaging stimuli. However, persistence of the harmful trigger, or a deficient resolution of the process can evolve into a state of low-grade, chronic inflammation. This condition is strongly associated to the development of several increasingly prevalent and serious chronic conditions such as obesity, cancer and cardiovascular diseases, elevating overall morbidity and mortality worldwide. The current pandemic of chronic diseases underscores the need to address chronic inflammation, its pathogenic mechanisms and potential preventive measures to limit its current widespread impact. The present review discusses the current knowledge and research gaps regarding the association between low-grade chronic inflammation and chronic diseases, focusing on obesity, cardiovascular diseases, digestive diseases and cancer. We examine the state-of-the-art in selected aspects of the topic, and propose future directions and approaches for the field.

Effects of Semaglutide on Muscle Structure and Function in the SLIM LIVER Study.

BACKGROUND: Semaglutide, a GLP-1 receptor agonist, is highly effective for decreasing weight. Concomitant loss of muscle mass often accompanies weight loss and may have consequences on muscle function. METHODS: This is a secondary analysis from the SLIM LIVER (ACTG A5371) study, a single-arm study of semaglutide in people with HIV (PWH) with metabolic dysfunction-associated steatotic liver disorder (MASLD). Participants received subcutaneous semaglutide for 24 weeks (titrated to 1 mg/week by week 4). Psoas volume and fat fraction were assessed from liver magnetic resonance imaging and physical function by 10-time chair rise test and 4m gait speed. Mean change from baseline to week 24 was estimated with linear regression modeling. RESULTS: 51 PWH enrolled; muscle measures were available from 46 participants. The mean age was 50 (standard deviation [SD] 11) years and BMI 35.5 (5.6) kg/m2, 43% were women, 33% Black, and 39% Hispanic/Latino. Psoas muscle volume decreased by 9.3% (95% confidence interval [CI]: -13.4, -5.2; p<0.001) over 24 weeks but psoas muscle fat did not significantly change (-0.42%, CI: -1.00, 0.17; p=0.16). Chair rise and gait speed had non-significant improvements of 1.27 seconds (CI: -2.7, 0.10) and 0.05 m/sec (CI: -0.01, 0.10), respectively (both p>0.07). The prevalence of slow gait speed (< 1 m/sec) decreased from 63% to 46% (p=0.029). CONCLUSIONS: In PWH receiving low-dose semaglutide for MASLD, despite decreased psoas muscle volume, there was no significant change in physical function. This suggests that function was maintained despite significant loss of muscle concomitant with weight loss.

Computational estimation of clonal diversity in autoimmunity.

Diversity is the cornerstone of the adaptive immune system, crucial for its effectiveness against constantly evolving pathogens that pose threats to higher vertebrates. Accurately measuring and interpreting this diversity presents challenges for immunologists, as changes in diversity and clonotype composition can tip the balance between protective immunity and autoimmunity. In this review, we present the current methods commonly used to measure diversity from single-cell T-cell receptor and B-cell receptor sequencing. We also discuss two case studies where single-cell sequencing and diversity estimations have led to breakthroughs in autoimmune disease discovery and therapeutic innovation, and reflect upon the necessity and importance of accurately defining and measuring lymphocyte diversity in these contexts.

Systemic immunometabolism and responses to vaccines: insights from T and B cell perspectives.

Vaccination stands as the cornerstone in the battle against infectious diseases, and its efficacy hinges on several host-related factors like genetics, age, and metabolic status. Vulnerable populations, such as malnourished individuals, the obese, and the elderly, commonly exhibit diminished vaccine responses and efficacy. While the specific factors contributing to this impairment may vary, these individuals typically display a degree of metabolic dysregulation, thereby underscoring its potential significance as a fundamental determinant of suboptimal vaccine responses. The emerging field of immunometabolism aims to unravel the intricate interplay between immune regulation and metabolic pathways, and recent research has revealed diverse metabolic signatures linked to various vaccine responses and outcomes. In this review, we summarize the major metabolic pathways utilized by B and T cells during vaccine responses, their complex and varied metabolic requirements, and the impact of micronutrients and metabolic hormones on vaccine outcomes. Furthermore, we examine how systemic metabolism influences vaccine responses and the evidence suggesting that metabolic dysregulation in vulnerable populations can lead to impaired vaccine responses. Lastly, we reflect on the challenge of proving causality with respect to the contribution of metabolic dysregulation to poor vaccine outcomes, and highlight the need for a systems biology approach that combines multimodal profiling and mathematical modelling to reveal the underlying mechanisms of such complex interactions.

Improving Machine Learned Force Fields for Complex Fluids through Enhanced Sampling: A Liquid Crystal Case Study.

Machine learned force fields offer the potential for faster execution times while retaining the accuracy of traditional DFT calculations, making them promising candidates for molecular simulations in cases where reliable classical force fields are not available. Some of the challenges associated with machine learned force fields include simulation stability over extended periods of time and ensuring that the statistical and dynamical properties of the underlying simulated systems are correctly captured. In this work, we propose a systematic training pipeline for such force fields that leads to improved model quality, compared to that achieved by traditional data generation and training approaches. That pipeline relies on the use of enhanced sampling techniques, and it is demonstrated here in the context of a liquid crystal, which exemplifies many of the challenges that are encountered in fluids and materials with complex free energy landscapes. Our results indicate that, whereas the majority of traditional machine learned force field training approaches lead to molecular dynamics simulations that are only stable over hundred-picosecond trajectories, our approach allows for stable simulations over tens of nanoseconds for organic molecular systems comprising thousands of atoms.

Moving beyond the constraints of chemistry via crystal structure discovery with isotropic multiwell pair potentials.

The rigid constraints of chemistry-dictated by quantum mechanics and the discrete nature of the atom-limit the set of observable atomic crystal structures. What structures are possible in the absence of these constraints? Here, we systematically crystallize one-component systems of particles interacting with isotropic multiwell pair potentials. We investigate two tunable families of pairwise interaction potentials. Our simulations self-assemble a multitude of crystal structures ranging from basic lattices to complex networks. Sixteen of the structures have natural analogs spanning all coordination numbers found in inorganic chemistry. Fifteen more are hitherto unknown and occupy the space between covalent and metallic coordination environments. The discovered crystal structures constitute targets for self-assembly and expand our understanding of what a crystal structure can look like.

Quantification of UV Light-Induced Spectral Response Degradation of CMOS-Based Photodetectors.

High-energy radiation is known to potentially impact the optical performance of silicon-based sensors adversely. Nevertheless, a proper characterization and quantification of possible spectral response degradation effects due to UV stress is technically challenging. On one hand, typical illumination methods via UV lamps provide a poorly defined energy spectrum. On the other hand, a standardized measurement methodology is also missing. This work provides an approach where well-defined energy spectrum UV stress conditions are guaranteed via a customized optical set up, including a laser driven light source, a monochromator, and a non-solarizing optical fiber. The test methodology proposed here allows performing a controlled UV stress between 200 nm and 400 nm with well-defined energy conditions and offers a quantitative overview of the impact on the optical performance in CMOS-based photodiodes, along a wavelength range from 200 to 1100 nm and 1 nm step. This is of great importance for the characterization and development of new sensors with a high and stable UV spectral response, as well as for implementation of practical applications such as UV light sensing and UV-based sterilization.

Pharmacogenetic interactions of efavirenz or rifampin and isoniazid with levonorgestrel emergency contraception during treatment of HIV or tuberculosis.

OBJECTIVE: In AIDS Clinical Trials Group study A5375, a pharmacokinetic trial of levonorgestrel emergency contraception, double-dose levonorgestrel (3 mg, versus standard dose 1.5 mg) offset the induction effects of efavirenz or rifampin on plasma levonorgestrel exposure over 8 h post-dose (AUC 0-8h ). We characterized the pharmacogenetics of these interactions. METHODS: Cisgender women receiving efavirenz- or dolutegravir-based HIV therapy, or on isoniazid-rifampin for tuberculosis, were followed after a single oral dose of levonorgestrel. Linear regression models, adjusted for BMI and age, characterized associations of CYP2B6 and NAT2 genotypes (which affect plasma efavirenz and isoniazid exposure, respectively) with levonorgestrel pharmacokinetic parameters. RESULTS: Of 118 evaluable participants, 17 received efavirenz/levonorgestrel 1.5 mg, 35 efavirenz/levonorgestrel 3 mg, 34 isoniazid-rifampin/levonorgestrel 3 mg, and 32 (control group) dolutegravir/levonorgestrel 1.5 mg. There were 73 Black and 33 Asian participants. Regardless of genotype, women on efavirenz and isoniazid-rifampin had higher levonorgestrel clearance. In the efavirenz/levonorgestrel 3 mg group, CYP2B6 normal/intermediate metabolizers had levonorgestrel AUC 0-8h values similar to controls, while CYP2B6 poor metabolizers had AUC 0-8h values of 40% lower than controls. In the isoniazid-rifampin group, NAT2 rapid/intermediate acetylators had levonorgestrel AUC 0-8h values similar to controls, while NAT2 slow acetylators had AUC 0-8h values 36% higher than controls. CONCLUSION: CYP2B6 poor metabolizer genotypes exacerbate the efavirenz-levonorgestrel interaction, likely by increased CYP3A induction with higher efavirenz exposure, making the interaction more difficult to overcome. NAT2 slow acetylator genotypes attenuate the rifampin-levonorgestrel interaction, likely by increased CYP3A inhibition with higher isoniazid exposure.

Acceptability and Feasibility of Providing Adherence Feedback Based on Tenofovir Diphosphate in Dried Blood Spots: Results from a Pilot Study Among Patients and Providers in Cape Town, South Africa.

Tenofovir diphosphate (TFV-DP) concentrations in dried blood spots (DBS) predict viral breakthrough, but their use remains understudied in real-world clinic settings. This pilot study examined acceptability, feasibility, and initial adherence outcomes of providing adherence feedback using TFV-DP concentrations on patient- and provider-levels in Cape Town, South Africa. We enrolled 60 persons with HIV (PWH) receiving tenofovir-containing ART attending a primary health clinic. They were randomized 1:1 to an intervention receiving TFV-DP concentration feedback by research staff vs. no feedback at monthly visits for 4 months. Acceptability among medical providers and level of clinical follow-up of TFV-DP results was examined. Patient acceptability was assessed descriptively. Mean electronic adherence (EA), as measured by WisePill device, and TFV-DP in DBS were compared between the two arms. All participants in the intervention group (100%) reported finding TFV-DP feedback helpful and 86% reported changing adherence behaviors. Medical providers indicated high acceptability of incorporating TFV-DP concentration feedback into the clinic, yet among 29 results < 1000 fmol/punch, only 2 were reviewed with no follow-up actions performed. In the intervention arm, mean TFV-DP concentrations were significantly higher (t = 2.5, p < .01) during follow-up and EA in upper quartile (96-100%) was greater compared to controls (x2 = 7.8, p ≤ .05). This study found high acceptability among patients for receiving adherence feedback based on TFV-DP concentrations. TFV-DP and EA data demonstrated greater adherence in the intervention group. Providers indicated high acceptability of incorporating TFV-DP feedback into the clinic, but few providers reviewed results, which could impact clinic-level feasibility.

TFH-derived dopamine accelerates productive synapses in germinal centres.

Protective high-affinity antibody responses depend on competitive selection of B cells carrying somatically mutated B-cell receptors by follicular helper T (TFH) cells in germinal centres. The rapid T-B-cell interactions that occur during this process are reminiscent of neural synaptic transmission pathways. Here we show that a proportion of human TFH cells contain dense-core granules marked by chromogranin B, which are normally found in neuronal presynaptic terminals storing catecholamines such as dopamine. TFH cells produce high amounts of dopamine and release it upon cognate interaction with B cells. Dopamine causes rapid translocation of intracellular ICOSL (inducible T-cell co-stimulator ligand, also known as ICOSLG) to the B-cell surface, which enhances accumulation of CD40L and chromogranin B granules at the human TFH cell synapse and increases the synapse area. Mathematical modelling suggests that faster dopamine-induced T-B-cell interactions increase total germinal centre output and accelerate it by days. Delivery of neurotransmitters across the T-B-cell synapse may be advantageous in the face of infection.

Endoscopic endonasal surgery for prolactinomas: prognostic factors for disease control and management of persistent disease.

Only a limited number of studies have focused on the results of the Endoscopic Endonasal Approach (EEA) for treatment of prolactinomas. We sought to assess the effectiveness of EEA for prolactinoma surgery, identify factors for disease remission, and present our approach for the management of persistent disease. Forty-seven prolactinomas operated over 10 years, with a mean follow-up of 59.9 months, were included. The primary endpoints were early disease remission and remission at last follow-up. Resistance/intolerance to DA were surgical indications in 76.7%. Disease remission was achieved in 80% of microprolactinomas and 100% of microprolactinomas enclosed by the pituitary. Early disease remission was correlated with female gender (p=0.03), lower preoperative PRL levels (p=0.014), microadenoma (p=0.001), lack of radiological hemorrhage (p=0.001), absence of cavernous sinus (CS) invasion (p<0.001), and extent of resection (EOR) (p<0.001). Persistent disease was reported in 48.9% of patients, with 47% of them achieving remission at last follow-up with DA therapy alone. Repeat EEA and/or radiotherapy were utilized in 6 patients, with 66.7% achieving remission. Last follow-up remission was achieved in 76.6%, with symptomatic improvement in 95.8%. Factors predicting last follow-up remission were no previous operation (p=0.001), absence of CS invasion (p=0.01), and EOR (p<0.001). Surgery is effective for disease control in microprolactinomas. In giant and invasive tumors, it may significantly reduce the tumor volume. A multidisciplinary approach may lead to long-term disease control in three-quarters of patients, with symptomatic improvement in an even greater proportion.

Phytochemical and Biological Profile of Essential Oils of Elionurus muticus (Spreng.) Growing in Northeastern Argentina.

The purpose of this study was to investigate essential oils (EOs) from leaves of Elionurus muticus growing in Northeastern Argentina regarding their physicochemical profiles as well as their biological potential. Roots of a selected E. muticus population were investigated too. For this purpose, EOs of fresh materials were obtained by steam distillation and the chemical composition was characterized by gas chromatography GC/MS-FID. Antibacterial, antioxidant and eco-toxicity activities of the essential oils (EOs) were tested by in vitro assays. The EOs showed three E. muticus chemotypes: citral (neral+geranial), acorenone+bisabolone, acorenone+geranial. EO of roots of citral population contains mainly acorenone derivatives. EOs have high antibacterial effect against Staphylococcus aureus, being found minor antibacterial effect against Gram-negative bacteria. The half-maximal inhibitory concentration of EOs against DPPH⋅ were 7.1-30.0 mg/mL and the eco-toxicity was high with LD50 <39 µg/mL. Based on the findings, given the high variability in their chemical composition and biological activity of E. muticus EO and the promising yields, it could be potentially chosen for industrial applications.

Characterization of a Clostridioides difficile ST-293 isolate from a recurrent infection in Argentina.

Clostridioides difficile is an opportunistic spore-forming pathogen responsible for antibiotic-associated diarrhea in humans. C. difficile produces two main toxins: TcdA and TcdB as well as a third toxin named binary toxin (CDT) that is also involved in virulence. The present study aimed at characterizing the C. difficile isolate ALCD3 involved in a relapse episode of nosocomial infection. Molecular characterization showed that isolate ALCD3 belongs to toxinotype 0/v and the MLST analysis demonstrated allelic profile adk:91, atpA:1, dxr:2, glyA: 1, recA:27, sodA: 1 and tpi:1 which corresponds to ST293 (MLST clade: 1). During growth, isolate ALCD3 showed an early increase in the sporulation ratio as well as maximal values of heat resistant forms after 2 days of incubation. Both sporulation kinetics and production of heat resistant forms were faster for isolate ALCD3 than for the reference strain VPI 10463. Germination in the presence of the natural germinant taurocholate was faster for isolate ALCD3 than for strain VPI 10463, which indicates that isolate ALCD3 starts cortex hydrolysis earlier than strain VPI 10463. Furthermore, the co-germinant glycine, induces rapid release of dipicolinic acid (DPA) in isolate ALCD3. These findings indicate that isolate ALCD3 is particularly efficient in both sporulation and germination. The present work represents the first report of the circulation of C. difficile ST293 in Argentina. The ability of isolate ALCD3 to produce toxins and its high sporulation/germination capacity are key features compatible with a microorganism with high dissemination potential and the possibility of inducing recurrent infections.