Recombinant Antibody Technology (United Kingdom)

Background and Objectives: Seroprevalence studies provide necessary data on extent of SARS-CoV-2 infection in a community. Identifying immune response of individuals exposed to this virus is one way of assessing community disease transmission and herd immunity. The aim of this study was to measure SARS- CoV-2 IgG antibody among adult individuals of Sialkot city overall and stratified by age and sex. Additionally, to describe COVID-19 presenting symptoms and its duration in these participants.
 Methods: This descriptive, cross-sectional study was undertaken in Sialkot city, where 453 participants completed in-person interview on COVID-19 symptoms, socio-demographic profile and provided 5ml blood sample for SARS-CoV-2 IgG antibody testing using electro-chemiluminescent immunoassay (ECLIA) technique. SPSS version 22 was utilized for data management and analysis. Sero-prevalence was calculated as percent of reactive for IgG among all tested. Chi-squared test was used for determining statistical significance with p <0.05 was considered significant.
 Results: Overall, sero-prevalence of SARS-CoV-2 IgG antibody among adults in Sialkot was 64%. Almost, 134(29.5%) of these positive for COVID-19 IgG antibody had antibody titres level 15 units/dl or above. Three out of every four individuals reported one or more symptoms of COVID-19 dry cough (17%), fever (30%) loss of taste (6%), sore throat (5%) and anosmia (4.6%).
 Conclusion: Almost two-third of adult population in Sialkot city had SARS-CoV-2 IgG antibody during 2021 survey that implies that herd immunity level for COVID-19 is achieved and negligible number of COVID-19 cases reported in Sialkot city supports this evidence.

<p>In this study, we present a hyper-spectral imaging (HSI) system that focuses on the spectral window 470-970 nm and meets the demands of static sampling and remote sensing when mounted on an Unmanned Aerial System (UAS).</p><p>The system comprises two HS cameras, a compact industrial PC and a battery pack. It has a total weight of <1.8kg, including the bracket for mounting to an active DJI Ronin gimbal. A labview interface was also developed to collect, process and analyse the images from the two HS cameras. The software has the ability to set the parameters for the cameras’ exposure times and capture frequency, while it can provide the digital counts at a single point of the image or the averaged counts over a rectangular area of the image. For the purposes of aerial applications, the program provides the ability of delayed start and sequentially image capture.</p><p>For the calibration of the raw HS images, an offline workflow is developed to derive absolute reflectance values. The processing chain includes dark and vignetting correction, spectral response characterization, digital number to reflectance conversion and hyperspectral data cube reconstruction.</p><p>The system has been already deployed in several in house studies: detection of dothistroma in Scots pine needles, starch detection in apples and bananas, and avocados maturity indication, while aerial imagery was also acquired during field campaigns in the UK and China aiming to create a tree species distribution map and to early identify tree health issues.</p><p>The development of the system is dynamic as technology is moving forward and the demand for light-weighted multi-sensor UAS surveys is increased during the last decade. Furthermore, the calibration processes and data analysis techniques are constantly updated to meet international requirements and push the accuracy of the products to the highest standards.</p>

Surgery is considered to be the favored approach for the treatment of most solid tumor malignancies. The quality of life among cancer patients has significantly improved due to advancements in instrumentation and surgical techniques; however, the recurrence of tumors and metastasis after operation remains challenging and results in a decreased quality of life and an increase in the mortality rate. Therefore, there is a need to explore applicable approaches to eradicate the circulating tumor cells and any residual tumor at the surgical site to inhibit the recurrence of the tumor and reduce the threat of distant metastasis. Recently drug delivery systems have been used to deliver immunotherapy or chemotherapy agents, which could augment the efficacy of surgical resection. In this review, we have summarized the efficacy and the recent progress of controlled drug delivery systems based approaches for post-surgical cancer treatment. Clinical translation challenges and opportunities have also been discussed.

Screening assays performed against membrane protein targets (e.g. phage display) are hampered by issues arising from protein expression and purification, protein stability in detergent solutions and epitope concealment by detergent micelles. Here, we have studied a fast and simple method to improve screening against membrane proteins: spherical-supported bilayer lipid membranes (“SSBLM”). SSBLMs can be quickly isolated via low-speed centrifugation and redispersed in liquid solutions while presenting the target protein in a native-like lipid environment. To provide proof-of-concept, SSBLMs embedding the polytopic bacterial nucleoside transporter NupC were assembled on 100- and 200 nm silica particles. To test specific binding of antibodies, NupC was tagged with a poly-histidine epitope in one of its central loops between two transmembrane helices. Fluorescent labelling, small angle X-ray scattering (SAXS) and cryo-electron microscopy (cryo-EM) were used to monitor formation of the SSBLMs. Specific binding of an anti-his antibody and a gold-nitrilotriacetic acid (NTA) conjugate probe was confirmed with ELISAs and cryo-EM. SSBLMs for screening could be made with purified and lipid reconstituted NupC, as well as crude bacterial membrane extracts. We conclude that SSBLMs are a promising new means of presenting membrane protein targets for (biomimetic) antibody screening in a native-like lipid environment.

Techniques to obtain large quantities of antigen-specific monoclonal antibodies (mAbs) were first established in the 1970s when Georges Köhler and César Milstein immortalized antibody-producing mouse B-lymphocytes by fusion with myeloma cells (http://www.whatisbiotechnology.org/exhibitions/milstein). Combined with the expression of human antibodies in transgenic animals, this technique allowed upon immunization the generation of highly specific fully human mAbs for therapeutic applications. Apart from being extremely beneficial, mAbs are a huge success commercially. However, despite cell fusion generating many useful mAbs questions have been asked about which types of cells are prone to fuse and whether other methods may identify a wider range of binders. The discovery that expression libraries, using Escherichia coli or yeast, produced different specificities was intriguing and more recently Next-Generation Sequencing has identified wide-ranging usage with highly diverse and unique repertoires. Another strategy is the combination of flow cytometry sorting of antigen-binding B lymphocytes and single-cell reverse transcription polymerase chain reaction followed by reexpression, which has identified many high-affinity mAbs.

ABSTRACTThe H3 loop in the Complementarity Determining Region of antibodies plays a key role in their ability to bind the diverse space of potential antigens. It is also exceptionally difficult to model computationally causing a significant hurdle for in silico development of antibody biotherapeutics. In this article, we show that most H3s have unique structural characteristics which may explain why they are so challenging to model. We found that over 75% of H3 loops do not have a sub‐Angstrom structural neighbor in the non‐antibody world. Also, in a comparison with a nonredundant set of all protein fragments over 30% of H3 loops have a unique structure, with the average for all of other loops being less than 3%. We further observed that this structural difference can be seen at the level of four residue fragments where H3 loops present numerous novel conformations, and also at the level of individual residues with Tyrosine and Glycine often found in energetically unfavorable conformations. Proteins 2017; 85:1311–1318. © 2017 Wiley Periodicals, Inc.

BackgroundThere is an ever-increasing need of monoclonal antibodies (mAbs) for biomedical applications and fully human binders are particularly desirable due to their reduced immunogenicity in patients. We have applied a strategy for the isolation of antigen-specific B cells using tetramerized proteins and single-cell sorting followed by reconstruction of human mAbs by RT-PCR and expression cloning.ResultsThis strategy, using human peripheral blood B cells, enabled the production of low affinity human mAbs against major histocompatibility complex molecules loaded with peptides (pMHC). We then implemented this technology using human immunoglobulin transgenic rats, which after immunization with an antigen of interest express high affinity-matured antibodies with human idiotypes. Using rapid immunization, followed by tetramer-based B-cell sorting and expression cloning, we generated several fully humanized mAbs with strong affinities, which could discriminate between highly homologous proteins (eg. different pMHC complexes).ConclusionsTherefore, we describe a versatile and more effective approach as compared to hybridoma generation or phage or yeast display technologies for the generation of highly specific and discriminative fully human mAbs that could be useful both for basic research and immunotherapeutic purposes.

Binding of hepatocyte growth factor (HGF) to the receptor tyrosine kinase MET is implicated in the malignant process of multiple cancers, making disruption of this interaction a promising therapeutic strategy. However, targeting MET with bivalent antibodies can mimic HGF agonism via receptor dimerization. To address this limitation, we have developed onartuzumab, an Escherichia coli-derived, humanized, and affinity-matured monovalent monoclonal antibody against MET, generated using the knob-into-hole technology that enables the antibody to engage the receptor in a one-to-one fashion. Onartuzumab potently inhibits HGF binding and receptor phosphorylation and signaling and has antibody-like pharmacokinetics and antitumor activity. Biochemical data and a crystal structure of a ternary complex of onartuzumab antigen-binding fragment bound to a MET extracellular domain fragment, consisting of the MET Sema domain fused to the adjacent Plexins, Semaphorins, Integrins domain (MET Sema-PSI), and the HGF β-chain demonstrate that onartuzumab acts specifically by blocking HGF α-chain (but not β-chain) binding to MET. These data suggest a likely binding site of the HGF α-chain on MET, which when dimerized leads to MET signaling. Onartuzumab, therefore, represents the founding member of a class of therapeutic monovalent antibodies that overcomes limitations of antibody bivalency for targets impacted by antibody crosslinking.