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Miller Fisher syndrome is one of the forms of Guillain–Barrе́ syndrome, characterized by a clinical triad that includes ophthalmoplegia, ataxia and areflexia, with the possible addition of moderate peripheral tetraparesis. During the year that has passed since the start of the pandemic of the new coronavirus infection COVID‑19, international publications have presented a few cases of Miller Fisher syndrome, which developed in patients at different times after the COVID‑19 infection – from 3–5 days to 3 weeks. The article presents a description of a clinical case of Miller Fisher syndrome, which occurred with 34‑year‑old man 21 days after the COVID‑19 infection. The clinical manifestations of Miller Fisher syndrome were typical and included diplopia, areflexia, and ataxia. At the beginning of the disease, there was a transient episode of speech impairment in the form of mild dysarthria. Oculomotor disorders predominated in the clinical picture over other components of the classical triad. On the background of treatment with human immunoglobulin G, there was a complete regression of symptoms.This description of Miller Fisher syndrome, which developed after the postponed infection with COVID‑19, is the first in Russia. The presented case demonstrates the ability of the SARS‑CoV‑2 virus to induce the development of an autoimmune disease. Practitioners should take into account the possibility of Miller Fisher syndrome developing in the event of an acute onset of diplopia, ataxia and areflexia in patients after a previous COVID‑19 infection.

A DNA aptamer screening method for human immunoglobulin G (IgG) Fc fragments was established based on capillary electrophoresis- systematic evolution of ligands by exponential enrichment (CE-SELEX). The purity, charged properties and non-adsorptivity of the samples of IgG, Fc and Fab were analyzed by capillary zone electrophoresis (CZE), and their affinity with ssDNA libraries was compared. The results showed that IgG formed significant complex with the ssDNA libraries, while Fc and Fab fragments exhibited weak affinity with the ssDNA libraries. Therefore, the use of the Fab fragment as the reverse screening target had no significant effect on the sequence except for the specific binding of Fc. The aptamer screening strategy for Fc fragments was designed. Aptamers (Seq Fc1–3) were obtained under optimized incubation conditions (10 mmol/L Na2HPO4-KH2PO4 (pH 7.17), 0.05 mmol/L Mg2+, incubated at 37 °C for 25 min) by three rounds of CE-SELEX, with KD values of 0.071–0.321 μmol/L, and their affinity and specificity were verified by AuNPs colorimetry assay.

A new strategy for ELISA-based detection in small volumes based on porous antibody-containing protein microparticles was developed and employed for the determination of human immunoglobulin G demonstrating both increase in sensitivity and decrease in antibody consumption by ten times compared to a conventional planar ELISA.

Graphical abstract This study reports the synthesis and characterization of the red nanophosphors Zn2SiO4:Eu3+ (ZSO:Eu3+) and Mg2TiO4:Mn4+ (MTO:Mn4+). The use of phosphors as a fluorescence label for lateral flow immunochromatographic assay (LFIA) has also been described. The optimal photoluminescence (PL) for ZSO:Eu3+ was obtained when it was synthesized with 7 mol% of Eu3+ and annealed at 1100 °C for 1 h. Long fluorescence lifetime (1.01 ms), high activation energy \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\it {\text{E}}_{\text{a}}$$\end{document}Ea (0.28 eV), and low PL degeneration (10% at 110 °C) are the characteristics of ZSO:Eu3+. MTO:Mn4+ also exhibited high PL intensity along with a high Ea of 0.32 eV. The emission wavelengths of phosphors are biocompatible with the optical bio-window of tissues. When human immunoglobulin G (human IgG) at a constant concentration of 100 μg/mL was used for detection, the PL ratios of the test line to the control line were 2.15 and 2.28 for the ZSO:Eu3+- and MTO:Mn4+-labeled LFIA, respectively. Thus, the ZSO:Eu3+ and MTO:Mn4+ nanophosphors are capable of human IgG recognition and are the promising candidates as fluorescent labels for on-site rapid optical biodetection. Supplementary Information The online version contains supplementary material available at 10.1007/s00339-021-04733-0.

Antiviral, antibacterial, and antiparasitic drugs and vaccines are essential to maintaining the health of humans and animals. Yet, their production can be slow and expensive, and efficacy lost once pathogens mount resistance. Chicken immunoglobulin Y (IgY) is a highly conserved homolog of human immunoglobulin G (IgG) that has shown benefits and a favorable safety profile, primarily in animal models of human infectious diseases. IgY is fast-acting, easy to produce, and low cost. IgY antibodies can readily be generated in large quantities with minimal environmental harm or infrastructure investment by using egg-laying hens. We summarize a variety of IgY uses, focusing on their potential for the detection, prevention, and treatment of human and animal infections.

Currently, antibodies are widely used not only in research but also in therapy. Hence, peptides that selectively bind to the fragment crystallizable site of an antibody have been extensively utilized in various research efforts such as the preparation of antibody–drug conjugates (ADC). Consequently, appropriate peptides that bind to immunoglobulin G (IgG) with a specific Kd value and also kon and koff values will be useful in different applications, and these kinetic parameters have been perhaps overlooked but are key to development of peptide ligands with advantageous binding properties. We prepared structural derivatives of IgG-binding peptide 1 and evaluated the binding affinity and kinetic rates of the products by surface plasmon resonance assay and isothermal titration calorimetry to obtain novel peptides with beneficial antibody binding properties. In this way, 15-Lys8Leu with fast-binding and slow-release features was obtained through a shortened peptide 15-IgBP. On the other hand, we successfully obtained distinctive peptide, 15-Lys8Tle, with a similar Kd value but with kon and koff values that were as much as six-fold different from those of 15-IgBP. These new peptides are useful for the elucidation of kinetic effects on the function of IgG-binding peptides and various applications of antibody or antibody–drug interactions, such as immunoliposome, ADC, or half-life extension strategy, by using a peptide with the appropriate kinetic features.

Alternative antibody-binding affinity ligands are expected to support robust time- and cost-effective antibody purification with rapid improvement of upstream productivity and demand on downstream process optimization. Five new tetrapeptide biomimetic affinity ligands (FYRH, HWRH, YHRI, HYRF, and FHRA) were screened by modeling the molecular interaction mechanism between tetrapeptide ligands and the Fc fragment of IgG with molecular dynamics simulation and the flexible docking method, and the corresponding five resins were prepared in this work to evaluate their adsorption characteristics of human immunoglobulin G (hIgG). The results showed that the binding capacities to hIgG of the five resins showed a strong pH-dependency, which was high at pH 7.0–9.0, and extremely low at pH 5.0–6.0, providing a benefit choice to separate hIgG. The dynamic binding capacities (DBC) at 10% breakthrough of five resins could reach up to 28–37 mg/mLgel, and Ac-FYRH-4FF resin showed the best adsorption performance. The eluti...

Owing to the high sensitivity, fast responsiveness and high specificity, immunoassays using surface-enhanced Raman scattering (SERS) as the readout signal displayed great potential in disease diagnosis. In this study, we developed a SERS-immunoassay method for the detection of human immunoglobulin G (HIgG). Upon involving well-ordered AuA on a SERSIA substrate, the LSPR effect was further enhanced to generate a strong and uniform Raman signal through the formation of sandwich structure with the addition of target HIgG and SERSIA tag. Optimization of the assay provided a wide linear range (0.1–200 μg mL−1) and low limit of detection (0.1 μg mL−1). In addition, the SERS-immunoassay method displayed excellent specificity and was homogeneous, which guaranteed the practical use of this method in the quantitative detection of HIgG. To validate this assay, human serum was analysed, which demonstrated the potential advantages of SERS-immunoassay technology in clinical diagnostics.

Nanobodies (Nbs) have recently emerged as a promising class of antibody fragments for biomedical and therapeutic applications. Despite having marked physicochemical properties, Nbs are derived from camelids and may require “humanization” to improve translational potentials for clinical trials. Here we have systematically analyzed the sequence and structural properties of Nbs based on NGS (next-generation sequencing) databases and high-resolution structures. Our analysis reveals substantial framework diversities and underscores the key differences between Nbs and human Immunoglobulin G (IgG) antibodies. We identified conserved residues that may contribute to enhanced solubility, structural stability, and antigen-binding, providing insights into Nb humanization. Based on big data analysis, we developed “Llamanade'', a user-friendly, open-source to facilitate rational humanization of Nbs. Using Nb sequence as input, Llamanade provides information on the sequence features, model structures, and optimizes solutions to humanize Nbs. The full analysis for a given Nb takes less than a minute on a local computer. To demonstrate the robustness of this tool, we applied it to successfully humanize a cohort of structurally diverse and highly potent SARS-CoV-2 neutralizing Nbs. Llamanade is freely available and will be easily accessible on a web server to support the development of a rapidly expanding repertoire of therapeutic Nbs into safe and effective trials.

A flexible, biological field-effect transistor (BioFET) for use in biosensing is reported. The BioFET is based on an organic thin-film transistor (OTFT) fabricated mainly by inkjet printing and subsequently functionalized with antibodies for protein recognition. The BioFET is assessed for label-free detection of a model protein, human immunoglobulin G (HIgG). It is characterized electrically to evaluate the contribution of each step in the functionalization of the OTFT and to detect the presence of the target protein. The fabrication, structure, materials optimization, electrical characteristics, and functionality of the starting OTFT and final BioFET are also discussed. Different materials are evaluated for the top insulator layer, with the aim of protecting the lower layers from the electrolyte and preserving the BioFET electrical performance., The authors thank the MICINN (projects MAT2011–25870 and TEC2011–29800) and the European Commission (FP7 project NADINE [contract # 246513]) for funding the research presented here.

In this study, the enhanced alkaline stability of Protein A ligands and resins designed by protein engineering approaches is demonstrated. High throughput PreDictor™ plates were used to evaluate and compare the human Immunoglobulin G (IgG) static binding capacities (SBC) of MabSelect SuRe™ and MabSelect™ PrismA affinity chromatography (AC) resins after continuous incubation in 0.1-2.0 M NaOH for 1-72 h. The alkaline effect on the Protein A affinity ligand was studied by high resolution mass spectrometry (MS). The IgG binding capacity of the investigated AC resins show expected declining trends with increasing NaOH concentrations and incubation times. The decrease is larger for MabSelect SuRe than for MabSelect PrismA and occur at lower NaOH concentrations. MabSelect SuRe display high remaining binding capacity even after 72 h continuous incubation in 0.1 M NaOH, while higher concentrations induce an accentuated decline with incubation time. The MabSelect PrismA resin shows almost no effect on the binding capacity even after 72 h incubation in 0.5 M NaOH. Decline in capacity is first observed after 48 h incubation in 1.0 M NaOH, thus displaying the extreme alkaline stability of the PrismA affinity ligand. The MS analysis of the ligands, including a Protein A single B-domain, SuRe-domain and PrismA-domain clearly illustrate the increasing alkaline stability (B-domain SuRe PrismA) as the ligand has been refined using a protein engineering approach. Deamidation and ligand degradation could be monitored in relation to NaOH incubation conditions. Enzymatic digestion of MabSelect SuRe and MabSelect PrismA resins after alkaline incubation and LC-MS/MS peptide mapping facilitates identification and quantification of specific deamidation sites on the affinity ligand.

A colorimetric immunosensor based on local surface plasmon resonance by gold nanoparticles is presented, and its application for the detection of human immunoglobulin G (IgG) is demonstrated. The color change of the colloidal solution is produced by nanoparticle aggregation, a process that can be tuned by the presence of the analyte once the nanoparticles are functionalized. In comparison to common functionalization techniques, the procedure described here is simpler, low-cost, and effective in binding antibodies upright on the gold surface. The dose–response curve is similar to that resulting in typical immunoassay platforms and is satisfactorily described by the proposed theoretical model. Human IgG at concentration levels of few hundreds of nanograms per milliliter can be detected by eyes within a few minutes, thereby making the colorimetric immunosensor proposed here a powerful tool in several areas, with urine test in medical diagnostics being the most immediate.

Las inmunoglobulinas son proteínas heterodiméricas compuestas de 2 cadenas pesadas y 2 cadenas ligeras. La inmunoglobulina G humana es un derivado del plasma y contiene más de 95 % de IgG. La composición de las subclases de IgG es similar a la del plasma humano normal. El tratamiento con inmunoglobulina comenzó hace más de 50 años y su uso se ha descrito en numerosas enfermedades. En Colombia, la importancia de este recurso inmunomodulador condujo a la necesidad de contar con una guía de práctica clínica para su uso, para lo cual se reunió un grupo multidisciplinario de expertos, quienes se distribuyeron en mesas de trabajo, por especialidad, para redactar un texto base. Se llevaron a cabo búsquedas bibliográficas sistemáticas; las evidencias identificadas se valoraron y clasificaron para sustentar un texto preliminar que fue discutido, analizado y corregido. Se emitieron recomendaciones de uso de la inmunoglobulina intravenosa en patologías que abarcan inmunodeficiencias primarias y secundarias, enfermedades autoinmunes, alteraciones neurológicas, infecciones, trasplantes y enfermedades misceláneas; se asignaron calificaciones según el sistema GRADE para cada una. El resultado final se tradujo en las recomendaciones que se presentan con la finalidad de informar, orientar y apoyar en el uso óptimo de dicho recurso inmunomodulador.

An enzyme-linked immunosorbent assay (ELISA) is reported for human immunoglobulin G based on synthesized hemin–MnO2 nanocomposite as the label. Enhanced sensitivity was obtained due to the increase...

Polyamines ω-aminohexyl and poly(ethyleneimine) (PEI) immobilized on agarose gel were evaluated as ligands for the purification of Fab fragments from papain-digested human immunoglobulin G (IgG) solution by negative chromatography. The adsorption of proteolytic fragments was investigated using different buffer systems and pH values. The results showed that the buffer system and pH had stronger effects on the adsorption of the proteolytic fragments onto ω-aminohexyl-agarose than onto PEI-agarose. Tris-HCl buffer pH 8.0 could be used to purify Fab fragments by negative chromatography using both adsorbents, achieving purity and recovery above 96% and 93%, respectively. Static binding experiments were conducted to determine the maximum binding capacity of ω-aminohexyl-agarose adsorbent (Qm). The experimental isotherm was best described by the Langmuir–Freundlich model, which indicated the positive cooperativity of adsorption (n = 1.68) and a Qm value of 44.32 mg mL−1 of gel. The results suggest that negative chromatography on ω-aminohexyl- and PEI-agarose is a potential technique for the purification of Fab fragments from papain-digested human IgG solution.

Background Spinal cord injury (SCI) is a condition with few effective treatment options. The blood-spinal cord barrier consists of pericytes, astrocytes, and endothelial cells, which are collectively termed the neurovascular unit. These cells support spinal cord homeostasis by expressing tight junction proteins. Physical trauma to the spinal cord disrupts the barrier, which leads to neuroinflammation by facilitating immune cell migration to the damaged site in a process involving immune cell adhesion. Immunosuppressive strategies, including methylprednisolone (MPSS), have been investigated to treat SCI. However, despite some success, MPSS has the potential to increase a patient’s susceptibility to wound infection and impaired wound healing. Hence, immunomodulation may be a more attractive approach than immunosuppression. Approved for modulating neuroinflammation in certain disorders, including Guillain-Barre syndrome, intravenous administration of human immunoglobulin G (hIgG) has shown promise in the setting of experimental SCI, though the optimal dose and mechanism of action remain undetermined. Methods Female adult Wistar rats were subjected to moderate-severe clip compression injury (35 g) at the C7-T1 level and randomized to receive a single intravenous (IV) bolus of hIgG (0.02, 0.2, 0.4, 1, 2 g/kg), MPSS (0.03 g/kg), or control buffer at 15 min post-SCI. At 24 h and 6 weeks post-SCI, molecular, histological, and neurobehavioral effects of hIgG were analyzed. Results At 24 h post-injury, human immunoglobulin G co-localized with spinal cord pericytes, astrocytes, and vessels. hIgG (2 g/kg) protected the spinal cord neurovasculature after SCI by increasing tight junction protein expression and reducing inflammatory enzyme expression. Improvements in vascular integrity were associated with changes in spinal cord inflammation. Interestingly, hIgG (2 g/kg) increased serum expression of inflammatory cytokines and co-localized (without decreasing protein expression) with spinal cord vascular cell adhesion molecule-1, a protein used by immune cells to enter into inflamed tissue. Acute molecular benefits of hIgG (2 g/kg) led to greater tissue preservation, functional blood flow, and neurobehavioral recovery at 6 weeks post-SCI. Importantly, the effects of hIgG (2 g/kg) were superior to control buffer and hIgG (0.4 g/kg), and comparable with MPSS (0.03 g/kg). Conclusions hIgG (2 g/kg) is a promising therapeutic approach to mitigate secondary pathology in SCI through antagonizing immune cell infiltration at the level of the neurovascular unit.

This work aimed to evaluate the interaction of human IgG in non-conventional adsorbents based on chitosan and alginate in the absence and presence of Reactive Green, Reactive Blue and Cibacron Blue immobilized as ligands. The adsorption was evaluated at 277, 288, 298 and 310 K using sodium phosphate buffer, pH 7.6, at 25 mmol L−1. The highest adsorption capacity was observed in the experiments performed with no immobilized dye, although all showed adsorption capacity higher than 120 mg g−1. Data modeling was done using Langmuir, Langmuir-Freundlich and Temkin classical nonlinear models, and artificial neural networks (ANN) for comparison. According to the parameters obtained, a possible adsorption in multilayers was observed due to protein-adsorbent and protein-protein interactions, concluding that IgG adsorption process is favorable and spontaneous. Using an ANN structure with 3 hidden neurons (single hidden layer), the MSE (RMSE) for training, test and validation were 13.698 (3.701), 11.206 (3.347) and 7.632 (2.763), respectively, achieving correlation coefficients of 0.999 in all steps. ANN modeling proved to be effective in predicting the adsorption isotherms in addition to overcoming the difficulties caused by experimental errors and/or arising from adsorption phenomenology.

Motivation The precise targeting of antibodies and other protein therapeutics is required for their proper function and the elimination of deleterious off-target effects. Often the molecular structure of a therapeutic target is unknown and randomized methods are used to design antibodies without a model that relates antibody sequence to desired properties. Results Here, we present Ens-Grad, a machine learning method that can design complementarity determining regions of human Immunoglobulin G antibodies with target affinities that are superior to candidates derived from phage display panning experiments. We also demonstrate that machine learning can improve target specificity by the modular composition of models from different experimental campaigns, enabling a new integrative approach to improving target specificity. Our results suggest a new path for the discovery of therapeutic molecules by demonstrating that predictive and differentiable models of antibody binding can be learned from high-throughput experimental data without the need for target structural data. Availability and implementation Sequencing data of the phage panning experiment are deposited at NIH’s Sequence Read Archive (SRA) under the accession number SRP158510. We make our code available at https://github.com/gifford-lab/antibody-2019. Supplementary information Supplementary data are available at Bioinformatics online.

Aim: We developed a platform to painlessly deliver by mouth drugs that cannot be administered orally. This ingestible, capsule-like device deploys inside the small intestine and injects into its wall a biotherapeutic payload sealed inside a dissolvable microneedle. Results: We tested the delivery and examined the pharmacokinetics of several biopharmaceuticals, including recombinant human insulin, human immunoglobulin G, octreotide and teriparatide in anesthetized and conscious pigs and dogs. The bioavailability of these compounds delivered by the capsules was similar to that after subcutaneous delivery. For instance, the mean peak serum concentration of insulin after capsule delivery in 8 anesthetized pigs was 517 ± 109 pmol/l, versus 342 ± 50 pmol/l after subcutaneous injection in 9 other, sham-operated pigs. In vivo safety studies were conducted in 23 conscious beagles, which received between 2 and 18 capsules. All devices transited painlessly through the GI tract and were excreted within 96 h. The mean gastric residence time (GRT) of the capsules was 93 min, and subsequent intestinal deployment time (IDT) was 28 minutes. A pilot study in 10 fasting and 10 postprandial human volunteers examined the tolerability and safety of the capsule devoid of microneedle and payload. The mean GRT of the capsule was 217 ± 36 min in the postprandial and 100 ± 79 min in the fasting state, while the IDT were closely similar (100 ± 40 vs. 97 ± 30 min) in both groups. No subject perceived the device transit, deployment or excretion. Conclusions: The studies completed thus far in anesthetized or conscious animals have confirmed that this ingestible device can deliver drugs in sufficient amounts and rate to obtain therapeutic blood concentrations. Its oral administration was well tolerated by the human subjects. First-in-man studies are being planned to test the ability of this ingestible device to deliver pharmaceuticals in healthy human volunteers and patients. Disclosure R. Ruffy: Employee; Self; RANI Therapeutics. M. Hashim: Board Member; Self; Rani Therapeutics. Employee; Self; InCube Labs LLC. A. Dhalla: Employee; Self; Rani Therapeutics, LLC. R. Korupolu: None. P. Karamchedu: Employee; Self; Incube labaoratories, Rani Therapeutics. B. Syed: None. R. Abdul Wahab: Employee; Self; Rani Therapeutics. S. Beraki: Employee; Self; InCube Laboratories, RANI Therapeutics. A. Yamaguchi: Employee; Self; Rani Therapeutics. L. Fusaro: None. A. Garapaty: None. A. Dasari: None. L. Fung: Employee; Self; Rani Therapeutics. Z.T. Al-Shamsie: Employee; Spouse/Partner; Google. Employee; Self; Rani Therapeutics, InCube Labs LLC. A. Toledo: Employee; Self; InCube Labs LLC, Rani Therapeutics. V. Salgotra: Employee; Self; Incubelabs, Rani Therapeutics. S. Sharma: None. E. Liang: None. D. Gratta: Employee; Self; InCube Labs, Rani Theraputics. M. Imran: Other Relationship; Self; InCube Labs, InCube Ventures, Rani Therapeutics.

The main aim of this study was to define the optimal adsorption and elution conditions for the purification of human immunoglobulin G (IgG) by mixed-mode chromatography using the multimodal resin Capto MMC. To this end, Central Composite Experimental Design (ED) was performed for both the adsorption and desorption stages. In the first case, the conditions were systematically studied in batch mode while in the latter case, these were performed in column. For both studies, the experimental design was conducted using high-purity human IgG samples. Buffer pH and concentration as well as the salt concentration were the parameters under study in the ED. Adsorption kinetics and equilibrium experiments were performed under the best conditions defined in the ED (phosphate buffer 60 mmol/L, pH 6.75, no salt). The equilibrium experimental data were fit to the Langmuir equation, with maximum uptake qmax equal to 549.2 mg/g. The qmax value found for IgG in Capto MMC was quite high as compared to other chromatographic techniques that employ single modes of interaction. Regarding elution, the best conditions were obtained with acetate buffer (56.40 mmol/L), pH 5.2 and 0.2 mol/L NaCl. An ultimate recovery of 46.96% for high-purity IgG was achieved. Thus, the effectiveness of Capto MMC for IgG adsorption and recovery could be confirmed. Moreover, electrophoretic runs in the human serum indicated that although co-elution of HSA and IgG proteins occurs, substantial HSA removal and a high IgG recovery were achieved in the elution step.

HIV-1 infection continues to be a global health challenge and a vaccine is urgently needed. Broadly neutralizing antibodies (bNAbs) are considered essential as they inhibit multiple HIV-1 strains, but they are difficult to elicit by conventional immunization. In contrast, non-neutralizing antibodies that correlated with reduced risk of infection in the RV144 HIV vaccine trial are relatively easy to induce, but responses are not durable. To overcome these obstacles, adeno-associated virus (AAV) vectors were used to provide long-term expression of antibodies targeting the V2 region of the HIV-1 envelope protein, including the potent CAP256-VRC26.25 bNAb, as well as non-neutralizing CAP228 antibodies that resemble those elicited by vaccination. AAVs mediated effective antibody expression in cell culture and immunocompetent mice. Mean concentrations of human immunoglobulin G (IgG) in mouse sera increased rapidly following a single AAV injection, reaching 8–60 μg/mL for CAP256 antibodies and 44–220 μg/mL for CAP228 antibodies over 24 weeks, but antibody concentrations varied for individual mice. Secreted antibodies collected from serum retained the expected binding and neutralizing activity. The vectors generated here are, therefore, suitable for the delivery of V2-targeting HIV antibodies, and they could be used in a vectored immunoprophylaxis (VIP) approach to sustain the level of antibody expression required to prevent HIV infection.

Assays for detecting tetanus toxoid are of great significance to be applied in the research of the safety testing of tetanus vaccine. Currently, guinea pigs or mice are usually used to evaluate the toxicity in these assays. Herein, a facile and quick biomineralization process was carried out to generate tetanus human immunoglobulin G (Tet-IgG)-functionalized Au nanoclusters (Tet-IgG-AuNCs). The obtained Tet-IgG-AuNCs exhibited strong red emission with a photoluminescence quantum yield of 13%. Based on surface plasmon resonance measurements, the apparent dissociation constant of the Tet-IgG-AuNC–tetanus toxoid complexes was measured to be 2.27 × 10−8 M. A facile detection approach was developed using a fluorescent Tet-IgG-AuNC–based immunochromatography test strip. By utilizing the high-brightness fluorescent Tet-IgG-AuNCs, this immunosensor showed favorable sensitivity with a detection limit at the level of 0.03 μg/mL. Further results demonstrated that this assay can reliably detect tetanus toxoid and therefore might provide a novel method to replace animal tests for the quantification of tetanus toxicity. Moreover, the antibody-AuNC-based immunochromatography test strip platform serves as a promising candidate to develop new approaches for detecting targeted antigens and biological events of interest.

Background/introduction The neuroinflammatory response plays a major role in the secondary injury cascade after traumatic spinal cord injury (SCI). To date, systemic anti-inflammatory medications such as methylprednisolone sodium succinate (MPSS) have shown promise in SCI. However, systemic immunosuppression can have detrimental side effects. Therefore, immunomodulatory approaches including the use of human immunoglobulin G (hIgG) could represent an attractive alternative. While emerging preclinical data suggests that hIgG is neuroprotective after SCI, the optimal time window of administration and the mechanism of action remain incompletely understood. These knowledge gaps were the focus of this research study. Methods Female adult Wistar rats received a clip compression-contusion SCI at the C7/T1 level of the spinal cord. Injured rats were randomized, in a blinded manner, to receive a single intravenous bolus of hIgG (2 g/kg) or control buffer at 15 minutes (min), 1 hour (h) or 4 h post-SCI. At 24 h and 8 weeks post-SCI, molecular, histological and neurobehavioral analyses were undertaken. Results At all 3 administration time points, hIgG (2 g/kg) resulted in significantly better short-term and long-term outcomes as compared to control buffer. No significant differences were observed when comparing outcomes between the different time points of administration. At 24 h post-injury, hIgG (2 g/kg) administration enhanced the integrity of the blood spinal cord barrier (BSCB) by increasing expression of tight junction proteins and reducing inflammatory enzyme expression. Improvements in BSCB integrity were associated with reduced immune cell infiltration, lower amounts of albumin and Evans Blue in the injured spinal cord and greater expression of anti-inflammatory cytokines. Furthermore, hIgG (2 g/kg) increased expression of neutrophil chemoattractants in the spleen and sera. After hIgG (2 g/kg) treatment, there were more neutrophils in the spleen and fewer neutrophils in the blood. hIgG also co-localized with endothelial cell ligands that mediate neutrophil extravasation into the injured spinal cord. Importantly, short-term effects of delayed hIgG (2 g/kg) administration were associated with enhanced tissue and neuron preservation, as well as neurobehavioral and sensory recovery at 8 weeks post-SCI. Discussion and conclusion hIgG (2 g/kg) shows promise as a therapeutic approach for SCI. The anti-inflammatory effects mediated by hIgG (2 g/kg) in the injured spinal cord might be explained in twofold. First, hIgG might antagonize neutrophil infiltration into the spinal cord by co-localizing with endothelial cell ligands that mediate various steps in neutrophil extravasation. Second, hIgG could traffic neutrophils towards the spleen by increasing expression of neutrophil chemoattractants in the spleen and sera. Overall, we demonstrate that delayed administration of hIgG (2 g/kg) at 1 and 4-h post-injury enhances short-term and long-term benefits after SCI by modulating local and systemic neuroinflammatory cascades.

In previous studies, hybridomas producing human immunoglobulin G, the antibodies 5E4 and 5A7 against influenza A and B virus were established using a novel human lymphocyte fusion partner, SPYMEG. In the present study, we succeeded in achieving the recombinant production and secretion of 5E4 and 5A7 in Chinese hamster ovary cells. Our N-glycan analysis by intact-mass detection and liquid chromatography mass spectrometry showed that recombinant 5E4 and 5A7 have one N-glycan and the typical mammalian-type N-glycan structures similar to those in hybridomas. However, the glycan distribution was slightly different among these antibodies. The amount of high-mannose-type structures was under 10% of the total N-glycans of recombinant 5E4 and 5A7, compared to 20% of the 5E4 and 5A7 produced in hybridomas. The amount of galactosylated N-glycans was increased in recombinants. Approximately 80% of the N-glycans of all antibodies was fucosylated, and no sialylated N-glycan was found. Recombinant 5E4 and 5A7 neutralized pandemic influenza A virus specifically, and influenza B virus broadly, quite similar to the 5E4 and 5A7 produced in hybridomas, respectively. Here we demonstrated that recombinants of antibodies identified from hybridomas fused with SPYMEG have normal N-glycans and that their neutralizing activities bear comparison with those of the original antibodies.

A maltose-functionalized metal-organic framework (MOF), MIL-101(Cr)-maltose, was developed via a simple two step post-synthetic modification of MIL-101(Cr)-NH2. With the use of this nanomaterial, 33 glycopeptides were detected from the digest of human immunoglobulin G, demonstrating its high efficiency in glycoproteomic analysis. More importantly, the generic functionalization route from amino-derived MOFs opens a new perspective in material design in sample preparation.

Mixed-mode chromatography (MMC) has been developed as a cost-effective new technique for antibody purification. Nuvia cPrime (NP) is a novel MMC resin with p-aminohippuric acid as the functional ligand. The adsorption of human immunoglobulin G (IgG) and bovine serum albumin (BSA) on NP was measured, including single component adsorption at different pH and binary coadsorption at various pH values and IgG/BSA mass ratios. Typical pH-dependent adsorption behavior was found in the single component adsorption which can be described by a two-parameter equation that offered a convenient way to analyze pH effects. Moreover, a competitive and preferential adsorption of IgG to BSA was investigated in binary coadsorption. Extended Langmuir (EL) and Extended Langmuir−Freundlich (ELF) models with parameters obtained from single-component isotherms were used to describe the coadsorption behaviors of IgG and BSA at various mass ratios. The results indicated the ELF model was more suitable for IgG adsorption, while the ...

Point-of-care testing (POCT) devices used in multiplex bioassays are in great demand for clinical, environmental and biomedical applications. Photonic crystal beads (PCBs), as structural color self-coding carriers, can be integrated with microfluidic chips to realize convenient and highly sensitive biomarker detection. Here we developed a three dimensional (3D) microfluidic chip based on PCBs, which is low cost and easy to manufacture for mass production and application. The chip was fabricated with polyethylene terephthalate, polymethyl methacrylate sheets, a Ni square mesh grid and transparent double-sided tape. In practice, the target molecules could be captured by PCBs immobilized with probes in a flow-through manner. It was found that the as-proposed chip needed less washing and its background was effectively reduced in comparison with a flow-over chip. Besides, the limit of detection (LOD) of anti-human alpha fetoprotein (AFP) was calculated to be 18.92 ng mL-1, which could meet the need of clinical detection of AFP. Furthermore, the chip demonstrated the feasibility of simultaneous detection of human immunoglobulin G, carcinoembryonic antigen and AFP, which suggests that it has a broad application prospect in multiplex bioassays.

Once-weekly (QW), subcutaneous efpeglenatide (efpeg) is a long-acting glucagon-like peptide 1 receptor agonist, with glucose- and weight-lowering effects, in development for type 2 diabetes (T2D). Efpeg is based on a single amino acid-modified exendin analog coupled to a fragment crystallizable (Fc) fragment of the human immunoglobulin G molecule for slow clearance that permits QW dosing. As immunogenicity may hamper pharmacological effects, the incidence of anti-drug antibodies (ADAs) was assessed in efpeg studies. In a cynomolgus monkey study, no primate developed ADAs (Table). In clinical dose-finding studies (efpeg exposure 3 months) are shown (Table). In patients with T2D or obesity, efpeg QW led to significant reductions in glycated hemoglobin and body weight, respectively, with low immunogenicity ( Disclosure S. Del Prato: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, GlaxoSmithKline plc., Intarcia Therapeutics, Inc., Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk A/S, Servier, Sanofi, Takeda Pharmaceuticals U.S.A., Inc.. Research Support; Self; Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Boehringer Ingelheim Pharmaceuticals, Inc., AstraZeneca. Speaker's Bureau; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Novartis Pharmaceuticals Corporation, Takeda Pharmaceuticals U.S.A., Inc.. Advisory Panel; Self; Janssen Biotech, Inc., Abbott. I. Choi: Employee; Self; Hanmi Pharmaceutical. Stock/Shareholder; Self; Hanmi Pharmaceutical. J. Kang: Employee; Self; Hanmi Pharmaceutical. M.E. Trautmann: Consultant; Self; ProSciento. Stock/Shareholder; Self; Eli Lilly and Company. Consultant; Self; Hanmi Pharmaceutical, CeQur Corporation, Intarcia Therapeutics, Inc., Servier. K. Yoon: None. C.H. Sorli: Employee; Self; Sanofi.

Fast and accurate quantitative measurement of biologically relevant molecules has been demonstrated for medical diagnostics and drug applications in photonic integrated circuits. Herein, we reported a highly-sensitive optical biosensor based on cascaded double-microring resonators. The sensor was integrated with microfluidic channels and investigated with its label-free detection capability. With a wavelength resolution of 0.47 nm, the measured binding capacity of the antibody on the surface exhibits reliable detection limit down to 7.10 μg/mL using human immunoglobulin G (hIgG).

The nanomechanical properties of single human immunoglobulin G and M antibodies were measured in a liquid environment using a fast force-volume technique with sub-10-nm spatial resolution. The ultrastructural details of these molecules were resolved in the images. Simultaneously, important physical properties, including elasticity, adhesion, and deformation were measured. The dimensions and adsorption of the immunoglobulin M antibodies onto the substrate indicated that they are highly flexible. The antibodies were characterized by a low elastic stiffness (34 ± 10 MPa) and high deformability (1.5 ± 0.5 nm).

A novel human immunoglobulin G (HIgG) electrochemical immunosensor was developed based on nanosilver-doped bovine serum albumin microspheres (Ag@BSA). The immunosensor was prepared step-wise by first modifying the electrode with β-cyclodextrin functionalized gold nanoparticles followed by the immobilization of captured antibodies and then the formation of a sandwich-type immunocomplex to introduce Ag@BSA bionanoprobes on the sensor surface. The amplification pathway using the stripping voltammetric measurement of silver ions released from Ag@BSA to monitor the immunoreaction was first adopted. The immunosensor exhibited a large dynamic range of 1 fg mL−1 to 10 pg mL−1 and an ultralow detection limit of 0.5 fg mL−1 to HIgG. Moreover, the immunosensor also showed acceptable stability and reproducibility. This biosensor was applied to the detection of the HIgG level in real serum samples.

A simple colorimetric immunoassay for quantification of human immunoglobulin G (hIgG) is herein described. The assay is based on the aggregation inhibition of silver nanoparticles (AgNP) functionalized with hIgG antibody (anti-hIgG) on the surface. The aggregation is measured in terms of attenuance values ratio at 400 and 530 nm (A400/A530). A linear response between A400/A530 and hIgG concentration is observed in the range 25 - 200 ng mL-1, and the detection limit is estimated as 11 ng mL-1 hIgG.

The rapid development of monoclonal antibodies (mAbs) in therapeutic and diagnostic applications has necessitated the advancement of mAbs purification technologies. In this study, a biomimetic small peptide ligand 3,5-di-tert-butyl-4-hydroxybenzoic acid-Arg-Arg-Gly (DAAG) functionalized monolith was fabricated through a metal ion chelation-based multi-step approach. The resulting monolith showed good chromatographic performance. Compared with the Ni2+ based IMAC monolith, the DAAG functionalized monolith exhibited not only excellent specificity but also higher dynamic binding capacity (DBC). The 10% DBC and 50% DBC for hIgG reached as high values as 26.0 and 34.6 mg/mL, respectively, at a ligand density of 8.8 μmol/mL, due to the high porosity and accessibility of the monolithic matrix. Moreover, the stability of the DAAG functionalized monolith in successive breakthrough experiments indicates that it has a promising potential for long-term use in mAbs purification. Finally, the DAAG functionalized monolith was successfully applied to the purification of trastuzumab or human immunoglobulin G (hIgG) from biological samples.

Arginine is widely used as aggregation suppressor of proteins in biotechnology and pharmaceutics. However, why the effect of arginine depends on the types of proteins and stresses, including monoclonal antibodies, is still unclear. Here we investigated the precise processes of the thermal aggregation of human immunoglobulin G (IgG) in the presence of additives. As expected, arginine was the best additive to suppress the formation of insoluble aggregates during heat treatment, though it was unable to preserve the monomer content. A systematic analysis of the additives showed that sugars and kosmotropic ion inhibit the formation of soluble oligomers. These behaviors indicate that the thermal aggregation of IgG occurs by (i) the formation of soluble oligomers, which is triggered by the unfolding process that can be stabilized by typical osmolytes, and (ii) the formation of insoluble aggregates through weak cluster-cluster interactions, which can be suppressed by arginine. Understanding the detailed mechanism of arginine will provide useful information for the rational formulation design of antibodies.

Monoclonal immunoglobulin G (IgG) is a multidomain protein. It has been reported that the conformational and colloidal stabilities of each domain are different, and it is predicted that limited domains participate in IgG aggregation. In contrast, the influence of interdomain interactions on IgG aggregation remains unclear. The fragment crystallizable (Fc) region is also a multidomain protein consisting of two sets of CH2 and CH3 domains. Here, we have analyzed the conformational change and aggregate size of an aglycosylated Fc region induced by both acid and salt stresses and have elucidated the influence of interdomain interactions between CH2 and CH3 domains on the conformational and colloidal stabilities of the aglycosylated Fc region. Singular value decomposition analyses demonstrated that the CH2 and CH3 domains unfolded almost independently from each other in the aglycosylated Fc region. Meanwhile, the colloidal stabilities of the CH2 and CH3 domains affect the aggregation process of the unfolded ag...

The use of artificial neural networks (ANNs) to predict the adsorption isotherms of human immunoglobulin G on immobilized Ni(II) affinity hollow fiber membranes was studied. Neural networks were trained using the Levenberg–Marquardt algorithm combined with Bayesian regularization technique and experimental data from different temperatures. The resulting neural network demonstrated to be able to interpolate the behavior of the maximum adsorption capacity and equilibrium concentration in the temperature range (4, 37 °C) with correlation coefficients higher than 0.96. Results demonstrated to be very similar to those achieved with traditionally Langmuir model adjustment. The advantage of interpolation ability of ANNs was also showed.

Primary immunodeficiencies (PIDs)* belong to the group of rare diseases which need more awareness by the relevant medical disciplines. Below a review on recent progresses in diagnosis and treatment of PIDs is given. Reducing the regrettable delay in diagnosis of PIDs (worldwide) is possible only when awareness is increased by doctors who may encounter patients with PID. This review shall serve this purpose. Progresses in understanding what the link might be between one genetic defect presenting in various phenotypes or how various gene defects may manifest by very similar PID phenotypes helps building awareness. Knowledge of PID favours early diagnosis, a cornerstone of optimal, sometimes life-long care at justifiable costs. The complexity of PIDs calls for clinical laboratory and clinical diagnostic performed by experts only. Exciting laboratory diagnostic progresses in early diagnosis of the most severe forms of PID are reviewed below. Progresses in curative therapies for PIDs, such as hematopoietic stem cell transplantation and gene therapies, are mentioned in short. About 80% of PID patients suffer from an antibody deficiency syndrome and can profit from non-curative replacement therapies with human immunoglobulin G concentrates. Modes of application, safety and hints for dosing of replacement therapies to reduce frequencies of severe infections are mentioned below. Thanks to the increasing quality of care, patients survive adolescence. A glance is given on the problems of transition to the adult medicine setting.

Antibodies can be directly immobilized on the surface of dialdehyde cellulose film through the covalent bonding of the aldehyde groups of the dialdehyde cellulose with amino groups of antibodies. In this work, human IgG was used as a model analyte to fabricate an electrochemical immunosensor. Using the proposed immunosensor, we detected IgG within the range from 0.5 to 45 ng/mL with a detection limit of 0.3 ng/mL (S/N = 3). The electrochemical immunosensor had a good specificity, stability and reproducibility. This strategy may pave a simple way to fabricate an electrochemical immunosensor in other applications.

In an earlier work, we have developed a biomimetic design strategy based on the human IgG (hIgG)-Protein A interactions and identified an affinity ligand for hIgG, FYWHCLDE, which ranked top one in a pool of 14 potential candidates. Herein, two more octapeptides, FYCHWALE and FYCHTIDE, were identified, and the binding and purification of hIgG on the affinity columns packed with the three octapeptide-modified Sepharose gels were extensively studied and compared to find more effective octapeptide-based affinity ligands. It was found that all the three ligands bound hIgG and Fc fragment but barely bound Fab fragment, and the binding to hIgG and Fc was mainly by electrostatic interactions. The optimum binding pH values for the three ligands were different from each other, but kept in the range of 5.0-6.0. Ligand binding competition revealed that the binding sites on hIgG for the three octapeptides were similar to those for Protein A. Adsorption isotherms revealed that hIgG binding capacity was in the range of 64-104mg/mL drained gel in the order of FYWHCLDE>FYCHWALE>FYCHTIDE. Then, purifications of hIgG and human monoclonal antibody from human serum and cell culture supernatant, respectively, were achieved with the three affinity columns at high purities and recovery yields. Finally, the molecular basis for the binding affinity of the peptides for the Fc fragment of hIgG was elucidated by molecular dynamics simulations.

In the present paper, we have studied human IgG in Alzheimer’s disease(AD) using nuclear magnetic resonance spectroscopy. A comparison with normal controls is also made. NMR spectroscopy is a powerful tool to detect the chemical groups of amino acids in serum. According to data available with the present study we are giving some of the findings related to AD patients. A group Aspartic acid (a-CH) is found in four cases only of AD patients and this group was absent in all the normal healthy persons. The group isoleucine (d-CH 3 ) has been found in all the blood samples of normal persons and AD patients. Glutamic acid (a-CH) is found in two cases of AD patients and was absent in all the normal persons and other patients of AD. Alanine (b-CH) is found in two cases of normal healthy people and four cases of AD patients only. Asparatic acid (a-CH) is found in four cases of AD patients only and absent in all the normal healthy people. Lysine ( g-CH 2 ) is found in one case of AD patient only and absent in all the normal healthy controls along AD patients. Isoleuicine (g- CH 3 ) has been found in three cases of AD patients only and four normal healthy people. Cystine (a-CH) and Cystine (b-CH) have been found in two cases of AD patients only and absent in all the normals with AD patients. Tryptophane (a-CH) is found in two sample of AD patient only and absent in all the cases of AD and normal healthy people . The appearance or disappearance of NMR groups may be changes in the CNS due to alteration in trace elements and immunity

Monolithic columns have attracted significant attention for the purification of large biomolecules. In the present study, a step gradient elution method was evaluated for the separation of human immunoglobulin G (hIgG) into its subclasses on CIM (convective interaction media) Gamma-protein A (recombinant protein A) monolithic column. hIgG was loaded onto the column and bound protein was eluted with a pH gradient. The subclass content of the eluted fractions was analyzed by enzyme-linked immunosorbent assay (ELISA). Results showed that separation of IgG3 from the other three subclasses can be successfully achieved with high selectivity (100%) and throughput on monolithic media. It was also revealed that enriched fractions of IgG1 and IgG2 could be obtained from purified hIgG in a 28 min long chromatographic run. Three fractions with high IgG1 content (89.1%, 94.3% and 88.8%) were recovered. Furthermore, IgG2 was enriched to 64% successfully. A rapid step gradient elution scheme without any additives in buffers was proven to obtain enriched preparations of the two important subclasses with high throughput. The separation time can be reduced even more by increasing the flow rate without any loss in selectivity, which will be beneficial in industrial scale applications.

Early diagnosis of diseases is critical in its effective management. Traditional disease detection methods require specialized equipment and trained personnel. With the introduction of rapid diagnostic test kits (RDTs), disease detection has become easier and faster. However, these RDTs have failed to compete with the specialized laboratory equipment due to their high detection limits and false alarm rates. This paper presents a novel method of using carbon nanofibers (CNFs) grown on glass microballoons (NMBs) to achieve ultra-low detection limits in RDTs. The NMBs have millions of nanosized CNFs grown on each microballoon, with each CNF having a strong bonding affinity for antibodies. The NMBs conjugated with secondary antibodies have therefore a significantly higher probability of capturing minute antigen concentrations in solution. Furthermore, the dark color formation at the capture zone makes visual disease detection possible. Human Immunoglobulin G (IgG) was selected as the model analyte to study the performance of NMBs using a sandwich immunoassay protocol. Ultra-low electrical detection limit of (4 pg/ml) and rapid re- sponse (~1 minute) was achieved using this method.

We describe a novel human immunoglobulin G2 (IgG2)-tolerant and immune-competent heterozygous mouse model (Xeno-het) developed by crossbreeding a human Ig-tolerized XenoMouse® with a C57BL/6J wild-type mouse. The Xeno-het mouse expresses both mouse and human immunoglobulin G (IgG) genes, resulting in B-cells expressing human and mouse IgG, and secretion of human and mouse Ig into serum. This model was utilized to evaluate the immunogenicity risk of aggregated and chemically modified human antibodies. The mice were tested for their ability to break tolerance to self-tolerant monomeric antibodies. Aggregates made by mechanical stirring elicited an anti-drug antibody (ADA) response, but did not induce a robust and long-term memory B and T-cell response. Chemically modified antibodies made by oxidation were only weak and transient inducers of an immune response, as measured by a lack of both an ADA response and a B-cell antigen-specific response. Aggregate size was an important characteristic, as specific-sized protein-coated beads were able to elicit an immune response. We propose the use of this model to identify risk factors such as aggregation during manufacturing at early development for an increased potential immunogenicity risk. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:3545–3555, 2013

Biologic agents have transformed clinical outcomes in rheumatoid arthritis, and there are now several immune-modulating therapies available. Tumour necrosis factor-α (TNF-α) inhibitors were the first biologic drug class licensed for the treatment of rheumatoid arthritis. Etanercept is a fusion protein composed of two TNF receptors bound to the constant portion (Fc) of human immunoglobulin G (IgG).This article will consider the pharmacological properties of etanercept and the clinical efficacy data presented in clinical trials. Its safety in clinical practice will be reviewed.There is overwhelming evidence to support the use of etanercept in rheumatoid arthritis. Trial data demonstrate etanercept's efficacy in reducing structural damage, improving clinical outcomes and inducing remission. Optimal response to therapy is seen when used in combination with methotrexate and when initiated early. Etanercept is an attractive therapeutic option given the excellent safety profile, reduced immunogenicity and ease of administration.

In this work, we presented a ratiometric electrochemical immunosensor based on redox substrate and immunoprobe. Carboxymethyl cellulose-Au-Pb2+ (CMC-Au-Pb2+) and carbon-Au-Cu2+ (C-Au-Cu2+) nanocomposites were firstly synthesized and implemented as redox substrate and immunoprobe with strong current signals at −0.45 V and 0.15 V, respectively. Human immunoglobulin G (IgG) was used as a model analyte to examine the analytical performance of the proposed method. The current signals of CMC-Au-Pb2+ (Isubstrate) and C-Au-Cu2+ (Iprobe) were monitored. The effect of redox substrate and immunoprobe behaved as a better linear relationship between Iprobe/Isubstrate and Lg CIgG (ng mL−1). By measuring the signal ratio Iprobe/Isubstrate, the sandwich immunosensor for IgG exhibited a wide linear range from 1 fg mL−1 to 100 ng mL−1, which was two orders of magnitude higher than other previous works. The limit of detection reached 0.26 fg mL−1. Furthermore, for human serum samples, the results from this method were consistent with those of the enzyme linked immunosorbent assay (ELISA), demonstrating that the proposed immunoassay was of great potential in clinical diagnosis.