Bifidobacterium modulation of tumor immunotherapy and its mechanism.

The advent of tumor immunotherapy in patients has revolutionized the treatment of tumors and significantly improved survival rates for a wide range of tumors. However, the full therapeutic potential of immune checkpoint inhibitors (ICIs) has yet to be realized, as not all patients have a lasting survival benefit from them, and a significant proportion of patients show primary or acquired resistance to immunotherapy. Bifidobacterium is one of the most common probiotics, and its antitumor and immunomodulatory effects have been demonstrated in recent years, but its immunomodulatory effects in tumors, especially on ICIs and in combination, have not been extensively studied in clinical practice, and its effects on the immune system and the mechanisms that modulate immunotherapy are largely unknown. Therefore, this review will focus on the immunomodulatory effects of Bifidobacteria in malignancies and the possible mechanisms of action of Bifidobacteria on immunotherapy in the hope of providing a basis for further research and better application of Bifidobacteria in clinical practice.

Regulation of Mycobacterium biofilm development and novel measures against antibiotics resistance.

Currently, there are over 170 recognized species of Mycobacterium, the only genus in the family Mycobacteriaceae. Organisms belonging to this genus are quite diverse with respect to their ability to cause disease in humans. The Mycobacterium genus includes human pathogens (Mycobacterium tuberculosis complex and Mycobacterium leprae) and environmental microorganisms known as non-tuberculosis mycobacteria (NTM). A common pathogenic factor of Mycobacterium is the formation of biofilms. Bacterial biofilms are usually defined as bacterial communities attached to the surface, and are also considered as shared spaces of encapsulated microbial cells, including various extracellular polymeric substrates (EPS), such as polysaccharides, proteins, amyloid proteins, lipids, and extracellular DNA (EDNA), as well as membrane vesicles and humic like microorganisms derived refractory substances. The assembly and dynamics of the matrix are mainly coordinated by second messengers, signaling molecules, or small RNAs. Fully deciphering how bacteria provide structure for the matrix, thereby promoting extracellular reactions and benefiting from them, remains a challenge for future biofilm research. This review introduces a five step development model for biofilms and a new model for biofilm formation, analyses the pathogenicity of biofilms, their interactions with bacteriophages and host immune cells, and the key genes and regulatory networks of mycobacterial biofilms, as well as mycobacterial biofilms and drug resistance, in order to provide a basis for clinical treatment of diseases caused by biofilms.

Invariant natural killer T cells recognize glycolipids from pathogenic Gram-positive bacteria.

Natural killer T cells (NKT cells) recognize glycolipid antigens presented by CD1d. These cells express an evolutionarily conserved, invariant T cell antigen receptor (TCR), but the forces that drive TCR conservation have remained uncertain. Here we show that NKT cells recognized diacylglycerol-containing glycolipids from Streptococcus pneumoniae, the leading cause of community-acquired pneumonia, and group B Streptococcus, which causes neonatal sepsis and meningitis. Furthermore, CD1d-dependent responses by NKT cells were required for activation and host protection. The glycolipid response was dependent on vaccenic acid, which is present in low concentrations in mammalian cells. Our results show how microbial lipids position the sugar for recognition by the invariant TCR and, most notably, extend the range of microbes recognized by this conserved TCR to several clinically important bacteria.

USP18-mediated protein deISGylation and its role in tuberculosis and other infectious diseases.

The transcription of interferon-stimulated gene 15 (isg15) is induced by type I interferons. ISG15 can covalently modify target proteins through the sequential action of enzymesE1, E2, and E3, a process known as ISGylation. The ISGylation of host proteins is widely involved in immune responses, such as host antiviral defence. Ubiquitin-specific protease 18 (USP18), as a deubiquitinase (DUB), can remove ISG15 conjugated to target proteins and inhibit host immune responses by suppressing the type I interferon signaling. The dynamic balance between ISGylation and deISGylation mediated by ISG15 or USP18 respectively plays a significant role in the tuberculosis. Furthermore, similar to ISG15, USP18 is extensively involved in virus-host interaction. In this review, we summarize the roles of ISGylation and deISGylation in tuberculosis and other important diseases mediated by ISG15 and USP18 respectively, underlying regulator network. Further studies in this aspect will inspire new host-targeted strategies to control important diseases such as tuberculosis.

Cyanidin-3-glucoside protects against high glucose-induced injury in human nucleus pulposus cells by regulating the Nrf2/HO-1 signaling.

Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin with antioxidant and anti-inflammatory properties. In this study, we explored the role and action mechanism of C3G in high glucose (HG)-induced damage of human nucleus pulposus cells (HNPCs). Cell viability was assessed by CCK-8 assay. TUNEL assay was performed for detecting apoptotic rate. Western blot was performed to determine the expression levels of cl-caspase-3, caspase-3, Bax, Bim, collagen II, aggrecan, MMP-3, MMP-13, and ADAMTS5. Reactive oxygen species (ROS) generation was analyzed using DCFH-DA staining. The Nrf2 was knocked down or overexpressed in HNPCs through transfection with si-Nrf2 or pcDNA3.0-Nrf2. C3G treatment (12.5, 25, and 50 µM) improved cell viability of HNPCs under HG condition. HG-induced cell apoptosis of HNPCs was attenuated by C3G with decreased apoptotic rate and relative levels of cl-caspase-3/caspase-3, Bax, and Bim. C3G treatment caused significant increase in expression levels of collagen II and aggrecan and decrease in the relative levels of MMP-3, MMP-13, and ADAMTS5. After treatment with C3G, ROS generation in HNPCs was markedly reduced. Treatment with N-acetylcysteine (NAC) reversed HG-induced cell apoptosis and extracellular matrix (ECM) degradation. C3G treatment induced the expression of Nrf2 and HO-1 in HG-induced HNPCs. Moreover, knockdown of Nrf2 reversed the inhibitory effect of C3G on ROS production. Summarily, C3G exerted a protective effect on ROS-mediated cellular damage in HNPCs under HG condition, which was attributed to the induction of the Nrf2/HO-1 signaling pathway.

Protective effects of Naoxintong capsule alone and in combination with ticagrelor and atorvastatin in rats with Qi deficiency and blood stasis syndrome.

CONTEXT: Naoxintong Capsule (NXT), a Chinese medicine, has been widely used for the treatment of coronary heart disease (CHD) in clinics. OBJECTIVE: This study evaluated the cardioprotective effects of NXT alone and in combination with ticagrelor (TIC) and atorvastatin (ATO). MATERIALS AND METHODS: Qi deficiency and blood stasis rats were established by 8 weeks high fat diet feeding and 16 days exhaustive swimming and randomly divided into seven groups, that is, NXT (250, 500 and 1000 mg/kg/d), TIC (20 mg/kg/d), ATO (8 mg/kg/d), NXT (500 mg/kg/d)+TIC (20 mg/kg/d) and NXT (500 mg/kg/d)+ATO (8 mg/kg/d) group, with oral administration for 12 weeks. The contents of TC, TG, LDL-C, HDL-C, IL-1ß, IL-6, IL-8, TNF-α, AST, ALT, SOD, MDA, CK-MB, LDH, TXA2, PGI2, IgA, IgG, IgM and C3 in serum were measured. RESULTS: NXT + TIC group was significantly superior to the TIC group in decreasing the levels of TC (4.34 vs. 5.54), TG (3.37 vs. 4.66), LDL-C (1.21 vs. 1.35), LDH (4919.71vs. 5367.19) and elevating SOD level (248.54 vs. 192.04). NXT + ATO group was significantly superior to the ATO group in decreasing the levels of AST (195.931 vs. 241.63), ALT (71.26 vs. 83.16), LDH (4690.05 vs. 5285.82), TXA2 (133.73 vs. 158.67), IgG (8.08 vs. 9.80), C3 (2.03 vs. 2.35) and elevating the levels of HDL-C (1.19 vs. 0.91), SOD (241.91vs. 209.49). CONCLUSIONS: The present findings demonstrate that the combined use of NXT with TIC and ATO had better integrated regulating effects than TIC and ATO, respectively. The mechanism of action requires further research.

Antioxidant Activity and Hepatoprotective Potential of Quercetin 7-Rhamnoside In Vitro and In Vivo.

Hypericum japonicum is traditionally used as a folk medicine to treat cholestasis and hepatitis. Quercetin 7-rhamnoside (Q7R) is one of the main flavonoid components of Hypericum japonicum and has been rarely studied. The aim of the present study was to evaluate the antioxidant activity and hepatoprotective potential of Q7R. In the in vitro experiments, DPPH, ABTS and ferric reducing antioxidant power (FRAP) assays were first performed to assess the antioxidant properties of Q7R, and then a H2O2-induced oxidative damage cellular model was used to determine the cytoprotective and antioxidant properties of Q7R in human liver L-02 cells. In the in vivo experiment, the hepatoprotective activity of Q7R was evaluated by carbon tetrachloride (CCl4)-induced liver damage model in mice. The results of the three in vitro assays (DPPH, ABTS and FRAP) demonstrated that Q7R significantly exhibited antioxidant activity. The cell experiment results showed that Q7R possessed cytoprotective and antioxidant effects on H2O2-treated L-02 cells. In the in vivo experiments, Q7R suppressed the up-regulation of serum activities of ALT, AST, LDH and triglyceride (TG) levels with dose-dependency. Q7R down-regulated the production of MDA and increased the hepatic GSH content and antioxidant enzymes CAT activities. Hepatic morphological analysis was also performed to confirm the biochemical changes. In summary, these results suggested that Q7R could be considered as a potential source of natural antioxidants, and may become a promising candidate for the treatment of liver injury in the future.

Chromatogram-Bioactivity Correlation-Based Discovery and Identification of Three Bioactive Compounds Affecting Endothelial Function in Ginkgo Biloba Extract.

Discovery and identification of three bioactive compounds affecting endothelial function in Ginkgo biloba Extract (GBE) based on chromatogram-bioactivity correlation analysis. Three portions were separated from GBE via D101 macroporous resin and then re-combined to prepare nine GBE samples. 21 compounds in GBE samples were identified through UFLC-DAD-Q-TOF-MS/MS. Correlation analysis between compounds differences and endothelin-1 (ET-1) in vivo in nine GBE samples was conducted. The analysis results indicated that three bioactive compounds had close relevance to ET-1: Kaempferol-3-O-α-l-glucoside, 3-O-{2-O-{6-O-[P-OH-trans-cinnamoyl]-ß-d-glucosyl}-α-rhamnosyl} Quercetin isomers, and 3-O-{2-O-{6-O-[P-OH-trans-cinnamoyl]-ß-d-glucosyl}-α-rhamnosyl} Kaempferide. The discovery of bioactive compounds could provide references for the quality control and novel pharmaceuticals development of GRE. The present work proposes a feasible chromatogram-bioactivity correlation based approach to discover the compounds and define their bioactivities for the complex multi-component systems.

Naringenin Regulates CFTR Activation and Expression in Airway Epithelial Cells.

BACKGROUND/AIMS: Sputum symptoms are commonly seen in the elderly. This study aimed to identify an efficacious expectorant treatment stratagem through evaluating the secretion-promoting activation and cystic fibrosis transmembrane conductance regulator (CFTR) expression of the bioactive herbal monomer naringenin. METHODS: Vectorial Cl- transport was determined by measuring short-circuit current (ISC) in rat airway epithelium. cAMP content was measured by ELISA in primary cultured epithelial cells and Calu-3 cells. CFTR expression in Calu-3 cells was determined by qPCR. RESULTS: Addition of naringenin to the basolateral side of the rat airway led to a concentration-dependent sustained increase in ISC. The current was suppressed when exposed to Cl--free solution or by bumetanide, BaCl2, and DPC but not by DIDS and IBMX. Forskolin-induced ISC increase and CFTRinh-172/MDL-12330A-induced ISC inhibition were not altered by naringenin. Intracellular cAMP content was significantly increased by naringenin. With lipopolysaccharide stimulation, CFTR expression was significantly reduced, and naringenin dose-dependently enhanced CFTR mRNA expression. CONCLUSION: These results demonstrate that naringenin has the ability to stimulate Cl- secretion, which is mediated by CFTR through a signaling pathway by increasing cAMP content. Moreover, naringenin can increase CFTR expression when organism CFTR expression is seriously hampered. Our data suggest a potentially effective treatment strategy for sputum.

Invariant NKT cells require autophagy to coordinate proliferation and survival signals during differentiation.

Autophagy regulates cell differentiation, proliferation, and survival in multiple cell types, including cells of the immune system. In this study, we examined the effects of a disruption of autophagy on the differentiation of invariant NKT (iNKT) cells. Using mice with a T lymphocyte-specific deletion of Atg5 or Atg7, two members of the macroautophagic pathway, we observed a profound decrease in the iNKT cell population. The deficit is cell-autonomous, and it acts predominantly to reduce the number of mature cells, as well as the function of peripheral iNKT cells. In the absence of autophagy, there is reduced progression of iNKT cells in the thymus through the cell cycle, as well as increased apoptosis of these cells. Importantly, the reduction in Th1-biased iNKT cells is most pronounced, leading to a selective reduction in iNKT cell-derived IFN-γ. Our findings highlight the unique metabolic and genetic requirements for the differentiation of iNKT cells.

Disc associating axial pain were indicated by PLL resection in ACDF surgery.

PURPOSE: The generation and tissue origination of disc-associated axial pain is still under exploration. This study was performed to evaluate disc-associated axial pain and to explore whether it originates in the disc or its surrounding components. METHODS: A 6-year series of 88 single-level Smith-Robinson disc and posterior longitudinal ligament (PLL) resections performed to treat single-level cervical spondylotic myelopathy was retrospectively examined. All single-level anterior disc decompressions were performed under local infiltration anesthesia; the PLL was not anesthetized to avoid cervical cord block. The patients were grouped by disc level. The centered foci of the pain localization were subjectively recorded before, during, and after the operation. Radiological examinations (plain X-ray, computed tomography, and magnetic resonance imaging) were performed before and after the operation to diagnose the compression and evaluate the decompression. RESULTS: All 88 patients who underwent single-level PLL resection had no intraoperative pain responses except during resection of the PLL. Their provoked pain responses were similar to their familiar pain responses. The axial pain disappeared postoperatively. Complications developed in six patients (6.8 %). All patients recovered well, and the absence of the axial pain was maintained at the 12-month follow-up. CONCLUSIONS: Preoperative axial pain due to single-level disc protrusion was triggered and aggravated only during PLL resection and disappeared postoperatively. This implies that the intervertebral PLL could be the site of origination of axial pain. Axial pain from the PLL at different disc levels had different distributions.

N16, a Nacreous Protein, Inhibits Osteoclast Differentiation and Enhances Osteogenesis.

N16 is a protein from the nacreous layer of Pinctada fucata, a pearl oyster. It has been found to promote biomineralization, and we hypothesized that it also plays a role in bone metabolism. The cDNA of N16 was cloned and expressed in Escherichia coli to produce N16 protein, which was purified to high homogeneity by ion-exchange and gel filtration columns. The effects of N16 on osteoclast differentiation and osteogenesis were clarified using the murine preosteoclast cell line RAW 264.7 and the preosteoblast cell line MC3T3-E1. Results on preosteoclasts showed that N16 only slightly inhibited cell survival but significantly inhibited differentiation induced by receptor activator of nuclear factor kappa-B ligand (RANKL). Apart from reduced formation of multinucleated osteoclasts, N16-treated cells exhibited lower gene expression and enzymatic activity typical of mature osteoclasts. Actin ring formation and intracellular acidification essential for osteoclastic function were also impaired upon N16 treatment. At concentrations nontoxic to preosteoblasts, N16 strongly up-regulated alkaline phosphatase activity and increased mineralized nodule formation, which are indicative of differentiation into osteoblasts. These effects coincided with an increase in mRNA expression of osteoblast markers osteopotin and osteocalcin. The present study demonstrated that N16 has both anabolic and antiresorptive effects on bone, which makes it potentially useful for treating osteoporosis.

Therapeutic effects of naringin in a guinea pig model of ovalbumin-induced cough-variant asthma.

Naringin, a well known component isolated from Exocarpium Citri Grandis, has significant antitussive effects. Recently, Naringin exhibited novel anti-inflammatory effect in chronic inflammatory diseases. In this work, we firstly evaluated the effects of naringin on enhanced cough, airway hyper-responsiveness (AHR), and airway inflammation in an ovalbumin-induced experimental cough-variant asthma (CVA) model in guinea pigs. We investigated the effect of naringin (18.4 mg/kg, per os, single dose or consecutively) on cough to inhaled capsaicin after challenge with an aerosolized antigen in actively sensitized guinea pigs. The effect of naringin on AHR to inhaled methacholine was evaluated 24 h after cough determination. Airway inflammation was assessed via bronchoalveolar lavage fluid (BALF) cytology and lung histopathology. Naringin, given consecutively, significantly reduced ovalbumin-induced enhanced cough and AHR, inhibited the increases in the leukocytes, interleukin-4 (IL-4), IL-5, and IL-13 in BALF compared with the model group. Moreover, the pathologic changes in lung tissues were clearly ameliorated by naringin treatment. These results suggest that naringin may be a beneficial agent for CVA treatment.

Unique interplay between sugar and lipid in determining the antigenic potency of bacterial antigens for NKT cells.

Invariant natural killer T (iNKT) cells are an evolutionary conserved T cell population characterized by features of both the innate and adaptive immune response. Studies have shown that iNKT cells are required for protective responses to Gram-positive pathogens such as Streptococcus pneumoniae, and that these cells recognize bacterial diacylglycerol antigens presented by CD1d, a non-classical antigen-presenting molecule. The combination of a lipid backbone containing an unusual fatty acid, vaccenic acid, as well as a glucose sugar that is weaker or not stimulatory when linked to other lipids, is required for iNKT cell stimulation by these antigens. Here we have carried out structural and biophysical studies that illuminate the reasons for the stringent requirement for this unique combination. The data indicate that vaccenic acid bound to the CD1d groove orients the protruding glucose sugar for TCR recognition, and it allows for an additional hydrogen bond of the glucose with CD1d when in complex with the TCR. Furthermore, TCR binding causes an induced fit in both the sugar and CD1d, and we have identified the CD1d amino acids important for iNKT TCR recognition and the stability of the ternary complex. The studies show also how hydrogen bonds formed by the glucose sugar can account for the distinct binding kinetics of the TCR for this CD1d-glycolipid complex. Therefore, our studies illuminate the mechanism of glycolipid recognition for antigens from important pathogens.

Protective effects of traditional Chinese medicine formula NaoShuanTong capsule on haemorheology and cerebral energy metabolism disorders in rats with blood stasis.

NaoShuanTong capsule (NSTC), an oral traditional Chinese medicine formula, is composed of Pollen Typhae, Radix Paeoniae Rubra, Rhizoma Gastrodiae, Radix Rhapontici and Radix Curcumae. It has been widely used to treat ischemic stroke in clinic for many years in China. In addition to neuronal apoptosis, haemorheology and cerebral energy metabolism disorders also play an important role in the pathogenesis and development of ischemic stroke. The present study was designed to evaluate the in vivo protective effects of NSTC on haemorheology and cerebral energy metabolism disorders in rats with blood stasis. Sixty specific pathogen-free sprague-dawley rats, male only, were randomly divided into six groups (control group, model group, aspirin (100 mg/kg/d) group, NSTC low-dose (400 mg/kg/d) group, NSTC intermediate-dose (800 mg/kg/d) group, NSTC high-dose (1600 mg/kg/d) group) with 10 animals in each. The rats except those in the control group were placed in ice-cold water (0-4 °C) for 5 min during the time interval (4 h) of two adrenaline hydrochloride injections (0.8 mg/kg) to induce blood stasis. After treatment, whole blood viscosity at three shear rates, plasma viscosity and erythrocyte sedimentation rate significantly decreased in NSTC intermediate- and high-dose groups; erythrocyte aggregation index and red corpuscle electrophoresis index significantly decreased in all the three dose NSTC groups. Moreover, treatment with high-dose NSTC could significantly improve Na+-K+ adenosine triphosphatase (ATPase) and Ca2+ ATPase activity, as well as lower lactic acid level in brain tissues. These results demonstrated the protective effects of NSTC on haemorheology and cerebral energy metabolism disorders, which may provide scientific information for the further understanding of mechanism(s) of NSTC as a clinical treatment for ischemic stroke. Furthermore, the protective effects of activating blood circulation as observed in this study might create valuable insight for the utilisation of NSTC to be a feasible alternative therapeutic agent for patients with blood stasis.

Involvement of S100A6/S100A11 in T-Cell Immune Regulatory in HCC Revealed by Single Cell RNA-seq.

Background: Immunotherapy plays a significant role in the treatment of hepatocellular carcinoma (HCC). Members of the S100 protein family (S100s) have been widely implicated in the pathogenesis and progression of tumors. However, the exact mechanism by which S100s contribute to tumor immunity remains unclear. Methods: To explore the role of S100s in HCC immune cells, we collected and comparatively analyzed single-cell RNA sequencing (scRNA-seq) data of HCC and hepatitis B virus-associated HCC. By mapping cell classification and searching for S100s binding targets and downstream targets. Results: S100A6/S100A11 was differentially expressed in tumor T cells and involved in the nuclear factor (NF) κB pathway. Further investigation of the TCGA dataset revealed that patients with low S100A6/S100A11 expression had a better prognosis. Temporal cell trajectory analysis showed that the activation of the NF-κB pathway is at a critical stage and has an important impact on the tumor microenvironment. Conclusion: Our study revealed that S100A6/S100A11 could be involved in regulating the differentiation and cellular activity of T-cell subpopulations in HCC, and its low expression was positively correlated with prognosis. It may provide a new direction for immunotherapy of HCC and a theoretical basis for future clinical applications.

Global emergence of double and multi-carbapenemase producing organisms: epidemiology, clinical significance, and evolutionary benefits on antimicrobial resistance and virulence.

Redundant carbapenemase-producing (RCP) bacteria, which carry double or multiple carbapenemases, represent a new and concerning phenomenon. The objective of this study is to conduct a comprehensive analysis of the epidemiology and genetic mechanisms of RCP strains to support targeted surveillance and control measures. A retrospective analysis was conducted using surveillance data from 277 articles. Statistical analysis was performed to determine and evaluate species prevalence, proportions of carbapenemases, antibiotic susceptibility profiles, sample information, and patient outcomes. Complete plasmid sequencing data were utilized to investigate potential antimicrobial resistance or virulence advantages that strains may gain from acquiring redundant carbapenemases. RCP bacteria are widely distributed globally, and their prevalence is increasing over time. Several countries, including China, India, Iran, Turkey, and South Korea, have reported more than 100 RCP strains. The most commonly reported RCP species are Klebsiella pneumoniae and Acinetobacter baumannii, which exhibit varying proportions of carbapenemase combinations. Certain species-carbapenemase combinations, such as K. pneumoniae carrying New Delhi metallo-ß-lactamase (NDM) + oxacillinase (OXA) (56.76%) and K. pneumoniae carbapenemase (KPC) + Verona integron-encoded metallo-ß-lactamase (VIM) (50.00%) carbapenemases, are associated with high mortality rates. In patients with RCP strains isolated from the bloodstream and respiratory system, the mortality rates are 58.70% and 69.23%, respectively. Analysis of plasmids from RCP strains suggests that they may acquire additional antibiotic resistance phenotypes and virulence factors. Carbapenem-resistant bacteria carrying redundant carbapenemases pose a significant global health threat. This study provides valuable insights into the epidemiology and genetic mechanisms of these bacteria, supporting the development of effective control and prevention strategies to mitigate their transmission.IMPORTANCEThis study examined the global distribution patterns of 1,780 bacteria with double or multiple carbapenemases from 277 articles and assessed their clinical impact. The presence of multiple carbapenemases increases the chances of co-resistance to other classes of antibiotics and more virulence factors, further complicating the clinical management of infections.

A Germinal Center Checkpoint of AIRE in B Cells Limits Antibody Diversification.

In response to antigens, B cells undergo affinity maturation and class switching mediated by activation-induced cytidine deaminase (AID) in germinal centers (GCs) of secondary lymphoid organs, but uncontrolled AID activity can precipitate autoimmunity and cancer. The regulation of GC antibody diversification is of fundamental importance but not well understood. We found that autoimmune regulator (AIRE), the molecule essential for T cell tolerance, is expressed in GC B cells in a CD40-dependent manner, interacts with AID and negatively regulates antibody affinity maturation and class switching by inhibiting AID function. AIRE deficiency in B cells caused altered antibody repertoire, increased somatic hypermutations, elevated autoantibodies to T helper 17 effector cytokines and defective control of skin Candida albicans. These results define a GC B cell checkpoint of humoral immunity and illuminate new approaches of generating high-affinity neutralizing antibodies for immunotherapy.

Metagenomic analysis of individual mosquito viromes reveals the geographical patterns and drivers of viral diversity.

Mosquito transmitted viruses are responsible for an increasing burden of human disease. Despite this, little is known about the diversity and ecology of viruses within individual mosquito hosts. Here, using a meta-transcriptomic approach, we determined the viromes of 2,438 individual mosquitoes (81 species), spanning ~4,000 km along latitudes and longitudes in China. From these data we identified 393 viral species associated with mosquitoes, including 7 (putative) species of arthropod-borne viruses (that is, arboviruses). We identified potential mosquito species and geographic hotspots of viral diversity and arbovirus occurrence, and demonstrated that the composition of individual mosquito viromes was strongly associated with host phylogeny. Our data revealed a large number of viruses shared among mosquito species or genera, enhancing our understanding of the host specificity of insect-associated viruses. We also detected multiple virus species that were widespread throughout the country, perhaps reflecting long-distance mosquito dispersal. Together, these results greatly expand the known mosquito virome, linked viral diversity at the scale of individual insects to that at a country-wide scale, and offered unique insights into the biogeography and diversity of viruses in insect vectors.

Identification of novel glycolipid ligands activating a sulfatide-reactive, CD1d-restricted, type II natural killer T lymphocyte.

Sulfatide-reactive CD1d-restricted natural killer T (NKT) lymphocytes belong to the type II NKT cell subset with diverse TCRs, and have been found to regulate experimental auto-immune encephalomyelitis, tumor immunity, and experimental hepatitis in murine models. NKT cells can be activated by self-lipids presented by CD1d, manifested as autoreactivity. The identity of most of these self-lipids remains unknown. By isolating lipids from a CD1d-expressing, highly stimulatory antigen presenting cell, we identified isoforms of ß-glucosylceramide (GlcCer), with sphingosine and fatty acid chain lengths of C24:0 and C16:0, that activated a sulfatide-reactive type II NKT cell hybridoma. A screen of structurally related glycosphingolipids demonstrated ß-galactosylceramide (GalCer) as another ligand, and further, that the lysoforms were the most potent isoform of the glycosphingo-lipid ligands, followed by isoforms with a long fatty acid chain of C24. Thus, the same type II NKT cell was activated by several ligands, namely sulfatide, GlcCer, and GalCer. However, CD1d-dependent reactivity to antigen presenting cells lacking all GlcCer-based glycosphingolipids, or all glycosphingolipids, was maintained. This suggests that other endogenous, nonglycosphingolipid, lipid ligands contribute to steady-state autoreactivity by type II NKT cells.