Yellow fever virus (YFV), a deadly human pathogen, is the prototype of the genus Flavivirus. Recently, YFV re-emerged in Africa and Brazil, leading to hundreds of deaths, with some cases imported to ...China. Prophylactic or therapeutic countermeasures are urgently needed. Previously, several human monoclonal antibodies against YFV were screened out by phage display. Here, we find that one of them, 5A, exhibits high neutralizing potency and good protection. Crystallographic analysis of the YFV envelope (E) protein in its pre- and post-fusion states shows conformations similar to those observed in other E proteins of flaviviruses. Furthermore, the structures of 5A in complex with the E protein in both states are resolved, revealing an invariant recognition site. Structural analysis and functional data suggest that 5A has high neutralization potency because it interferes with virus entry by preventing both virus attachment and fusion. These findings will be instrumental for immunogen or inhibitor design.
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•The crystal structures of YFV-E in both pre- and post-fusion states are determined•A neutralizing monoclonal antibody engages YFV-E in both states as a double lock•This monoclonal antibody inhibits YFV infection at multiple steps of virus entry
Yellow fever virus (YFV) is a deadly flavivirus. Lu et al. report the structures of YFV envelope protein in its pre- and post-fusion states and a potent neutralizing monoclonal antibody bound to both states. Structural and functional analyses reveal the double lock of the antibody to neutralize YFV infection.
Interleukin-31 (IL-31) is a pro-inflammatory cytokine involved in skin inflammation and tumor progression. The IL-31 signaling cascade is initiated by its binding to two receptors, IL-31 receptor ...alpha (IL-31RA) and oncostatin M receptor subunit beta (OSMRβ). The previous study suggested that human IL-31 (hIL-31) directly interacts with IL-31RA and OSMRβ, independently, but the binding ability of hIL-31 to IL-31RA is stronger than to OSMRβ. In different to its human ortholog, feline IL-31 (fIL-31) has a higher binding affinity for feline OSMRβ. However, the binding pattern of canine IL-31 to its receptors remains to be elucidated. In this study, we purified the recombinant canine IL-31 (rcIL-31) protein and revealed its secondary structure to be mainly composed of alpha-helices. Moreover, in vitro studies show that rcIL-31 has the ability to induce the phosphorylation of signal transducer activator of transcription 3 (STAT3) and STAT5 in DH-82 cells. In the following, the binding efficacies of bioactive rcIL-31 for its individual receptor components have been measured using a flow cytometry assay. The result demonstrates that correctly refolded rcIL-31 binds independently with cIL-31RA and cOSMRβ which were expressed on the cell surface. Of note, rcIL-31 has a greater than tenfold higher affinity to OSMRβ than to IL-31RA. Additionally, we demonstrated that D1–D4, especially D4 of cOSMRβ, is crucial for its binding to cIL-31. Furthermore, this study proved that rcIL-31 has a high binding affinity to the soluble cOSMRβ with a KD value of 3.59 × 10
–8
M. The results presented in the current study will have a significant implication in the development of drugs or antibodies against diseases induced by cIL-31 signaling.
The isolation of human monoclonal antibodies with broadly neutralizing breadth can provide a promising countermeasure for influenza A viruses infection. Most broadly neutralizing antibodies against ...influenza A viruses bind to the conserved stem region or the receptor-binding cavity of hemagglutinin and the interaction is dominated by the heavy chain. The light chain, however, contributes few or no direct contacts to the antigen. Here we report an H3-clade neutralizing human monoclonal antibody, AF4H1K1, which recognizes the hemagglutinin glycoproteins of all group 2 influenza A viruses. This human monoclonal antibody has been obtained through the screening by pairing different heavy and light chains from an H7N9-infected patient based on the next-generation sequencing technology. Further structural studies revealed that light chains modulate the neutralizing spectrum by affecting the local conformation of heavy chains, instead of direct interaction with the antigen. These findings provide important clues to understand the molecular basis of light chains in antigen recognition and to explore the strategies in particular of the use of light chain modification to develop broadly protective monoclonal antibodies against influenza A viruses and other emerging viruses.
Oncostatin M receptor beta (OSMRβ) mediates signaling of Oncostatin M (OSM) and interleukine-31 (IL-31), two key cytokines involved in many important biological processes including inflammation and ...cancer progression. More importantly, OSMRβ might be a potential biomarker and therapeutic target for some diseases, such as inflammatory bowel disease, pruritus and ovarian cancer. In this study, soluble recombinant canine OSMRβ (cOSMRβ) was experimentally expressed as a native antigen to develop an effective cOSMRβ-specific monoclonal antibody (mAb), 2O2, using hybridoma technology. It was demonstrated that 2O2 is able to detect OSMRβ expressed on cell surface using immunofluorescence assay (IFA) and flow cytometry (FACS). This mAb exhibits very high binding affinity to cOSMRβ with the KD and half-maximal effective concentration (EC50) values of 2.49 nM and 96.96 ng/ml, respectively. Meanwhile, it didn't show any cross-relativities with feline OSMRβ (fOSMRβ) and human OSMRβ (hOSMRβ). Moreover, we determined the binding epitope of 2O2, which localizes in the domain VI (DVI, amino acids 623–734) of cOSMRβ. In conclusion, this novel mAb, 2O2, can be used in immunoassays, including IFA, FACS and enzyme-linked immunosorbent assay (ELISA) to facilitate studies in dogs.
•OSMRβ is a potential target of treatment against inflammatory diseases and cancers induced by IL-31- or OSM-related axis.•A novel mAb, 2O2, specific for canine OSMRβ was developed and characterized.•2O2 shows a high specificity and binding affinity for canine OSMRβ.•2O2 is able to detect OSMRβ expressed on cell surface using IFA and FACS assays.•The binding epitope of 2O2 localize at the domain VI (amino acids 623–734) of canine OSMRβ.
T cell immune responses have played pivotal roles in host immune protection against Mycobacterium tuberculosis (MTB) infection. MTB specific antigen, Rv3615c (EspC), was identified to be as ...immunodominant as the well-known ESAT-6 and CFP-10, and has brought promising expectations to more sensitive T-cell based diagnosis and vaccine development. However, limited knowledge about the immunogenicity and diagnostic values of this antigen has restricted its application in clinical practice. Herein, the Rv3615c antigen was identified as a robust CTL immunoantigen with broadly cross-human leucocyte antigen (HLA) allele recognized peptides which may contribute to the broad recognition of Rv3615c antigen among the population. A three-antigen-cocktail (3-Ag-cocktail) comprising of ESAT-6, CFP-10 and Rv3615c was investigated in a multicenter, randomized and double-blinded study to evaluate its clinical diagnostic performances. A significantly improved sensitivity was demonstrated against the 3-Ag-cocktail compared with that against ESAT-6 and CFP-10. Both responsive magnitude and sensitivity were significantly lower in patients concurrently suffering from cancer, indicating its restriction in diagnosis of immunocomprised patients. In conclusion, inclusion of the Rv3615c antigen with multiple HLA restricted CTL epitopes would benefit the T-cell based diagnosis of MTB infection.
Abstract
We present a self-powered, high-performance graphene-enhanced ultraviolet silicon Schottky photodetector. Different from traditional transparent electrodes, such as indium tin oxides or ...ultra-thin metals, the unique ultraviolet absorption property of graphene leads to long carrier life time of hot electrons that can contribute to the photocurrent or potential carrier-multiplication. Our proposed structure boosts the internal quantum efficiency over 100%, approaching the upper-limit of silicon-based ultraviolet photodetector. In the near-ultraviolet and mid-ultraviolet spectral region, the proposed ultraviolet photodetector exhibits high performance at zero-biasing (self-powered) mode, including high photo-responsivity (0.2 A W
−1
), fast time response (5 ns), high specific detectivity (1.6 × 10
13
Jones), and internal quantum efficiency greater than 100%. Further, the photo-responsivity is larger than 0.14 A W
−1
in wavelength range from 200 to 400 nm, comparable to that of state-of-the-art Si, GaN, SiC Schottky photodetectors. The photodetectors exhibit stable operations in the ambient condition even 2 years after fabrication, showing great potential in practical applications, such as wearable devices, communication, and “dissipation-less” remote sensor networks.
Abstract With the advent of induced pluripotent stem cells and directed differentiation techniques, it is now feasible to derive individual-specific cardiac cells for human heart tissue engineering. ...Here we report the generation of functional engineered human cardiac patches using human induced pluripotent stem cells-derived cardiac cells and decellularized natural heart ECM as scaffolds. The engineered human cardiac patches can be tailored to any desired size and shape and exhibited normal contractile and electrical physiology in vitro . Further, when patching on the infarct area, these patches improved heart function of rats with acute myocardial infarction in vivo . These engineered human cardiac patches can be of great value for normal and disease-specific heart tissue engineering, drug screening, and meet the demands for individual-specific heart tissues for personalized regenerative therapy of myocardial damages in the future.
Cascaded h-bridges (CHBs) and dual active bridges (DABs) are often used to build power electronics transformers (PETs), of which the multi-bus PET will become an extended structure. Generally, the ...output power on each bus may not be equal due to different load demands, resulting in a power imbalance. Accordingly, the ratio of output power on each bus is used to describe the imbalance degree. If the boundary of power imbalance degree is uncertain, the performance of PETs in terms of stability and capability will be limited. Addressing the stability issue of PETs in an imbalance degree, the accurate boundary of the stable operation region should be analyzed. To this end, a geometrical solution based on the steady-state phasor model in the complex vector coordinate frame is proposed for the PET with a dual-bus structure. Furthermore, the quantitative relation between the bus voltage and the power imbalance degree is analyzed. It is found that the boundary of the imbalance degree is mainly determined by the bus voltage and the number of DABs. By selecting a reasonable number of DABs, the operation region and the stability of PETs can be improved. Finally, the feasibility and correctness of the proposed method are verified through simulations and a hardware-in-loop experimental platform.
•The article investigates UV light excited gas sensing properties based on rGO functionalized with different contents of hollow SnO2 nanofibers.•The greatly enhanced selective detection to NO2 and ...SO2 is achieved, the response ratio of NO2/SO2 is up to 9.3 by using UV light illumination.•The modulation effect of UV light assistance on gas detection is demonstrated.•Sensing mechanism analysis of the UV light activated rGO/SnO2 sensors is studied.
Herein, to enhance selective detection of NO2 and SO2 using a single device, an ultraviolet (UV) light activated gas sensor has been reported based on reduced graphene oxide (rGO) functionalized with hollow SnO2 nanofibers (NFs) at room temperature. The porous hollow SnO2 NFs are synthesized using electrospinning and calcination treatment, then different contents of SnO2 are introduced to rGO for preparation of rGO/SnO2 nanocomposites by facile magnetic stirring and ultrasonic treatment. The rGO/SnO2 samples reveal obvious sensing response, great reversibility and good humidity resistance to target gases at ppm level. Under different intensities of UV light illumination, gas sensing properties of rGO/SnO2 are studied to explore the photoexcited sensing behaviors. The greatly enhanced selective detection to NO2 (102%) and SO2 (11%) is achieved with a response ratio of 9.3 by using UV light illumination. The results show sensor response and selectivity can be improved using appropriate intensity of excitation light, demonstrating significant modulation effect of UV light assistance on gas detection. The mechanism may be attributed to light motivated electron-hole pairs due to built-in electric fields under UV light illumination, which can be captured by target gases and lead to UV controlled gas sensing performance.
Three variable 2 (V2) loops of HIV-1 envelope glycoprotein (Env) trimer converge at the Env apex to form the epitope of an important classes of HIV-1 broadly neutralizing antibodies (bNAbs). These ...V2-glycan/apex antibodies are exceptionally potent but less broad (∼60 to 75%) than many other bNAbs. Their CDRH3 regions are typically long, acidic, and tyrosine sulfated. Tyrosine sulfation complicates efforts to improve these antibodies through techniques such as phage or yeast display. To improve the breadth of CAP256-VRC26.25 (VRC26.25), a very potent apex antibody, we adapted and extended a B cell display approach. Specifically, we used CRISPR/Cas12a to introduce VRC26.25 heavy- and light-chain genes into their respective loci in a B cell line, ensuring that each cell expresses a single VRC26.25 variant. We then diversified these loci through activation-induced cytidine deaminase-mediated hypermutation and homology-directed repair using randomized CDRH3 sequences as templates. Iterative sorting with soluble Env trimers and further randomization selected VRC26.25 variants with successively improving affinities. Three mutations in the CDRH3 region largely accounted for this improved affinity, and VRC26.25 modified with these mutations exhibited greater breadth and potency than the original antibody. Our data describe a broader and more-potent form of VRC26.25 as well as an approach useful for improving the breadth and potency of antibodies with functionally important posttranslational modifications.
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