Photo-switchable Collectors for the Flotation of Lithium Aluminate for the Recycling of the Critical Raw Material Lithium.

Flotation of the mineral lithium aluminate by application of the natural product punicine from Punica granatum and some derivatives as collectors is examined. Punicines, 1-(2',5'-dihydroxyphenyl)-pyridinium compounds, are switchable molecules whose properties can be changed reversibly. They exist as cations, neutral mesomeric betaines, anions, and dianions depending on the pH. In light, they form radicals. Five punicine derivatives were prepared which possess ß-methyl, ß-chlorine, γ-tert.-butyl, and γ-acetyl groups attached to the pyridinium ring, and a pyrogallol derivative. On the other hand, LiAlO2 reacts with water to give species such as LiAl2(OH)7 on its surface. Flotations were performed applying the punicines in daylight (3000 lux), in darkness (<40 lux) and under UV-irradiation (4500 lux, 390-400 nm). The pH of the suspension, the collector's concentration, the conditioning time as well as the flotation time were varied. The recovery rates strongly depend on these parameters. For example, the recovery rate of lithium aluminate was increased by 116 % on changing the lighting condition from daylight to darkness, when the pyrogallol derivative of punicine was applied. UV, FTIR, TGA and zeta potential measurements as well as DFT calculations were performed in order to gain insight into the chemistry of punicines on the surface of LiAlO2 and LiAl2(OH)7 in water which influence the flotation's results.

Lithium aluminate flotation by pH- and light-switchable collectors based on the natural product punicine.

Derivatives of the natural product punicine [1-(2',5'-dihydroxyphenyl)pyridinium chloride] were developed as switchable collectors for the flotation of lithium-containing engineered artifical minerals (EnAMs). These EnAMs are e.g. formed by pyrometallurgical processing of end-of-life lithium-ion batteries. Depending on the pH value and the lighting conditions, punicines exist in water as cations, two different electrostatically neutral mesomeric betaines, anionic tripoles, radical cations or radical anions. The radical species form by photochemically induced disproportionation reactions. We prepared punicine derivatives introducing alkyl chains in the pyridinium moiety (4-methyl, 4-ethyl, 4-octyl and 4-undecanyl) to install hydrophobic groups and examined the recovery rates of the flotation of lithium aluminate (LiAlO2). We varied the lighting conditions (darkness, daylight, LED irradiation at λ = 390-400 nm) and the pH value, the collector's and frother's concentration, and the flotation time. With our collectors, recovery rates of lithium aluminate up to 90% were accomplished when the flotation was conducted in Hallimond tubes exposed to daylight at pH 11 in water.

Stability assessment of anti-bacterial antibodies in immunoglobulin G-depleted serum with validated immunoassays.

Aim: To investigate the stability of the anti-pneumococcal (PCP) and anti-haemophilus type B (Hib) immunoglobulins (IgGs) in human IgG-depleted serum samples frozen at -20°C. Materials & methods: Modified commercially available immunoassays (ELISAs) were bioanalytically validated. These ELISAs were used to measure levels of the two anti-bacterial IgG in samples kept at -20°C for up to 15 months. Human IgG-depleted serum was spiked with GAMMAGARD Liquid to obtain those samples. Results: Both ELISAs passed the validation test. Anti-PCP IgG and anti-Hib IgG were shown to be stable for at least 15 months at -20°C. Conclusion: These data confirm the stability of anti-bacterial IgG in human IgG-depleted serum and support the common practice of testing frozen samples.

Immunodeficiency disorders can prevent your body from fighting infections. These disorders make it easier to catch viruses and bacterial infections caused by so-called pathogens. Patients suffering from immunodeficiencies are treated throughout their lives with antibodies purified from human plasma. This immunoglobulin replacement therapy, which helps to avoid infections, provides specific antibodies directed against these pathogens. An antibody is a protein produced by the body's immune system to detect (bind) antigens and to help eliminating harmful substances. Little is known about the stability of such specific antibodies in samples taken from patients during clinical studies carried out to improve the replacement therapy. We investigated the stability of two such antibodies using a standard technique for their measurement. In a process termed validation, these methods were demonstrated to deliver accurate and precise results. For the stability study, we prepared human serum (= the liquid part of human blood) samples with specific antibodies levels expected in samples from patients on replacement therapy. These samples were kept frozen at -20°C for up to 15 months. The data obtained on analysis of the frozen samples showed the adequate stability of both antibodies directed against important pathogen. This stability confirms a common testing practice applied for samples obtained in clinical studies where usually such samples are not tested immediately but are stored frozen and tested in batches. In particular, the data for the two anti-bacterial antibodies support the storage of such samples for at least 15 months at -20°C before testing.

Macromolecular Architecture-Dependent Polymorphous Crystallization Behavior of PVDF in the PVDF/γ-BL System via Thermally Induced Phase Separation.

This study investigates the effect of the macromolecular architecture of poly(vinylidene fluoride) (PVDF) on its thermally induced phase separation (TIPS) behavior and polymorphic crystallization in the PVDF/γ-butyrolactone (PVDF/γ-BL) system. Preparative PVDF fractions with specific macromolecular architecture and phase constitution are generated. The results show that PVDF's macromolecular architecture, particularly the degree of branching and regio-defects, plays a significant role in its temperature-dependent crystallization and resulting polymorphic phases. While regio-defects dominate crystallization in the temperature range between 30 and 25 °C, the degree of branching becomes decisive in the 25-20 °C interval. The developed fractions of PVDF are further analyzed in terms of their molecular weight distribution, revealing that the PVDF fractions crystallized out of solution have similar molecular weight distributions with lower dispersity compared with the feed polymer. These findings are crucial for macromolecular separation and adjustment of PVDF polymorphic properties and hence for the development of tailor-made PVDF matrix materials for composites and membranes. The findings suggest the possibility of polymorphous phase tailoring of PVDF based on macromolecular architecture due to temperature-controlled crystallization out of solution and strongly motivate further research to reveal deeper knowledge of regio-defect and branching influence of PVDF solution crystallization.

Selective and sensitive measurement of human neutrophil elastase in clinical samples based on a novel assay principle for protease activity measurement.

Imbalances between proteases and protease inhibitors have been associated with several pathological conditions including emphysema as seen in α1-antitrypsin deficiency. For this pathological condition, unimpeded neutrophil elastase activity has been ascribed a pivotal role in the destruction of lung tissue and thus in disease progression. Therefore, low, or non-quantifiable neutrophil elastase (NE) activity levels determined in bronchoalveolar lavage solutions indicate the success of α1-antitrypsin (AAT) augmentation therapy as NE activity will be erased. To overcome the known limitations of available elastase activity assays regarding sensitivity and selectivity, we developed a new elastase activity assay, which fundamentally relies on the highly specific complex formation between AAT and active elastase. Plate-bound AAT captured active elastase from the sample undergoing complex formation, followed by the immunological detection of human NE. This assay principle facilitated the measurement of low pM amounts of active human NE. The data of the assay performance check demonstrated adequate accuracy and precision profiles meeting currently accepted best practices for this activity assay, which can be classified as a ligand-binding assay. Furthermore, spike-recovery studies at low human NE levels, carried out for three human bronchoalveolar samples, resulted in recoveries within the 100 ± 20% range, while good linearity and parallelism of the samples' dilution-response curves was observed. Altogether, complemented by the data of selectivity and robustness studies and the accuracy and precision profile obtained in buffer, this newly developed human NE activity assay was demonstrated to perform accurately and precisely in clinically relevant samples.

Gas Phase Reaction of Silane with Water at Different Temperatures and Supported by Plasma.

The interaction of silane and water is discussed controversially in literature: some authors suggest monosilane and water react kinetically and sufficiently fast enough to remove water, while others state the reaction occurs only at elevated temperatures. This question is of technological interest for the removal of unavoidable water residues in Ar gases. Thermodynamic calculations show that virtually complete removal of water is expected with superstoichiometric silane addition. However, mass spectrometric and infrared spectroscopic experiments give evidence that the addition of monosilane to such an Ar gas at room temperature is unable to remove residual water, which disagrees with some current hypotheses in the literature. This holds even for very high SiH4 concentrations up to 2 vol.-%. Silane reacts with water above temperatures of 555 °C, initiated by the thermal decomposition of silane. A cold dielectric barrier discharge-plasma used for silane and water dissociation enhances reactivity similar to elevated temperatures. Fourier-transformed infrared spectroscopy points toward silanol generation at temperatures between 400 and 550 °C, while quadrupole mass spectrometry indicates the creation of SiOH+, SiHOH+, SiH2OH+, and SiH3OH+. Cold plasmas generate smaller amounts of SiOH+, SiHOH+, and SiH2OH+ compared to elevated temperatures. Reaction products are hydrogen and nanoscaled particles of non-stoichiometric silicon oxides. The silicon-oxide particles produced differ in elemental composition and shape depending on the prevailing water content during decomposition: SiO x generated with residual water appears with relatively smooth surfaces, while the addition of water supports the formation of significantly rougher particle surfaces. Higher initial water contents correlate with higher oxygen contents of the particles.

Selective human factor VIII activity measurement after analytical in-line purification.

Background: It is essential to measure the activity of factor VIII (FVIII) throughout the life cycle of a coagulation FVIII concentrate. Such measurement in nonclinical pharmacokinetic studies is potentially biased by the presence of endogenous nonhuman FVIII, and certain manufacturing process-related additives can also impact the assay performance. Finally, the presence of FVIII activity-mimicking antibodies poses challenges when measuring FVIII in samples. Therefore, we developed an antibody-based chromogenic FVIII assay, which facilitates the selective and sensitive activity measurement of human FVIII in the presence of animal plasma and interfering agents. Methods: Plate-bound monoclonal anti-FVIII antibody specifically captured human FVIII, which was then measured with a chromogenic activity assay. A human reference plasma preparation was used to construct the calibration curve. Spike recovery was carried out in a citrated cynomolgus monkey plasma-solvent/detergent mixture and in the presence of the bispecific antibody emicizumab. Results: The calibration curve ranged from 3.03 to 97.0 mIU FVIII/ml and was obtained repeatedly with good accuracy. B domain-deleted and full-length FVIII did not differ in their responses. Recovery of spiked human FVIII in citrated cynomolgus monkey plasma was 102.7%, while neither native monkey plasma nor the other animal specimen tested showed any activity. Solvent/detergent solution and the bispecific antibody emicizumab had no influence on the assay. Conclusion: Combining antibody-mediated specific capture of human FVIII and a chromogenic activity assay resulted in a selective and sensitive measurement of human FVIII with no interference by endogenous, nonhuman FVIII, manufacturing process additives, or an FVIII activity-mimicking antibody.

Sensitive and specific measurement of alpha1-antitrypsin activity with an elastase complex formation immunosorbent assay (ECFISA).

Functionally active alpha1-antitrypsin (AAT) is measured predominantly with a chromogenic elastase inhibition assay, where the concentration of AAT activity inversely correlates with the levels of residual elastase. This standard assay has moderate sensitivity as it hardly allows the measurement of samples containing less than 10 µg of functionally active AAT per mL. To overcome this drawback, we developed a new assay format for the measurement of functionally active AAT, which we termed the elastase complex formation immunosorbent assay (ECFISA). The ECFISA uses plate-bound, still proteolytically active elastase, which attacks functionally active AAT under irreversible formation of a stable stochiometric 1 + 1 complex. This complex is then detected and measured by an anti-AAT peroxidase conjugate. Using three different approaches for the preparation of functionally inactive AAT - heating, oxidation, and complex formation with elastase - we confirmed beyond doubt that the ECFISA exclusively measures functionally active AAT and that these measurements are unimpaired by the presence of high concentrations of functionally inactive AAT. Studies addressing the coating procedure demonstrated that adequate and robust conditions had been defined for this essential first step of the ECFISA. Possible interference caused by the presence of important plasma proteinase inhibitors in the test samples could be excluded for the most abundant inhibitors. Even a 1.5-times molar excess of alpha2-macroglobulin over AAT was shown to have no impact, which is not the case for a conventional chromogenic activity assay. Functional activities determined with the ECFISA and validated chromogenic elastase inhibition assay matched well with a mean absolute bias of 0.64% calculated for the 25 samples measured. The results of the bioanalytical assay validation complied with the acceptance criteria for ligand-binding assays as given by current guidelines on validation of bioanalytical methods. Overall, the data obtained demonstrated the ECFISA as an accurate, precise, selective, and very sensitive method for AAT activity measurement at low levels previously inaccessible for direct measurement.

Biochemical and cellular markers differentiate recovered, in-line filtered plasma, and plasma obtained by apheresis methods.

BACKGROUND AND OBJECTIVES: Assessment of plasma quality often focuses on the common safety tests for minimizing the risk of transmitting blood-borne pathogens. Little attention is paid to the possible quality attributes that ensure a consistent biochemical composition of plasma for fractionation. We therefore investigated the suitability of selected biochemical and haematological attributes that could be used as markers of plasma quality obtained by different separation and pre-treatment procedures. MATERIAL AND METHODS: We characterized six plasma types, including source plasma, plasma recovered by classic means and in-line filtered plasma, by determining the analytical attributes protein content, coagulation factors and markers of coagulation, contact and complement activation. Residual cell content and cell-specific variables were also measured. RESULTS: We found relevant differences between the plasma types in complement activation, as indicated by C3a measurements, while thrombin antithrombin complex values and, to a minor extent, activated factor XII concentrations indicated only moderate differences in activation levels of coagulation and contact systems. The most striking differences, however, were detected in residual cell content and concentrations of the platelet-associated proteins, platelet factor 4 and ß-thromboglobulin. We showed that leucocyte reduction filters disrupt cells. This includes platelets, thereby releasing the platelet-associated proteins platelet factor 4 and ß-thromboglobulin, and leucocytes as demonstrated by the release of elastase from polymorphonuclear leucocytes. Furthermore, the filtration processing of whole blood can lead to activation of the complement system. CONCLUSION: Our results show that biochemical and cellular surrogate markers are valuable discriminators of plasma types.

Interaction of Reactive Gases with Platinum Aerosol Particles at Room Temperature: Effects on Morphology and Surface Properties.

Nanoparticles produced in technical aerosol processes exhibit often dendritic structures, composed of primary particles. Surprisingly, a small but consistent discrepancy was observed between the results of common aggregation models and in situ measurements of structural parameters, such as fractal dimension or mass-mobility exponent. A phenomenon which has received little attention so far is the interaction of agglomerates with admixed gases, which might be responsible for this discrepancy. In this work, we present an analytical series, which underlines the agglomerate morphology depending on the reducing or oxidizing nature of a carrier gas for platinum particles. When hydrogen is added to openly structured particles, as investigated by tandem differential mobility analysis (DMA) and transmission electron microscopy (TEM) analysis, Pt particles compact already at room temperature, resulting in an increased fractal dimension. Aerosol Photoemission Spectroscopy (APES) was also able to demonstrate the interaction of a gas with a nanoscaled platinum surface, resulting in a changed sintering behavior for reducing and oxidizing atmospheres in comparison to nitrogen. The main message of this work is about the structural change of particles exposed to a new environment after complete particle formation. We suspect significant implications for the interpretation of agglomerate formation, as many aerosol processes involve reactive gases or slightly contaminated gases in terms of trace amounts of unintended species.

Fabrication of large pore mesoporous silica microspheres by salt-assisted spray-drying method for enhanced antibacterial activity and pancreatic cancer treatment.

Large-pore mesoporous silica (LPMS) microspheres with tunable pore size have received intensive interest in the field of drug delivery due to their high storage capacity and fast delivery rate of drugs. In this work, a facile salt-assisted spray-drying method has been developed to fabricate LPMS microspheres using continuous spray-drying of simple inorganic salts as pore templates and colloidal SiO2 nanoparticles as building blocks, followed by washing with water to remove the templates. More importantly, the porosity of the LPMS microspheres can be finely tuned by adjusting the furnace temperature and relative concentration of the salt to SiO2, which could lead to optimal pharmaceutical outcomes. Then, the biological roles of these LPMS microspheres were evaluated in antibacterial and cancer therapy. In this regard, rhodamine b as a probe was initially loaded inside the LPMS microspheres. The obtained particles not only showed high entrapment efficiency (up to 30%) and a pH-responsive drug release but also presented pore-size-controlled drug release performance. Then, in vitro antibacterial activities of multiple antibiotics, namely nalidixic acid, chloramphenicol, and ciprofloxacin, loaded in the LPMS particles were investigated against two pathogenic bacteria, Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The results indicated bacterial inhibition up to 70% and 20% in less than 2 h for Escherichia coli and Staphylococcus aureus, respectively. This inhibition of bacterial growth was accompanied by no bacterial regrowth within 30 h. Finally, the versatility of LPMS microspheres as drug carriers in pancreatic cancer treatment was explored. In this regard, a pro-apoptotic NCL antagonist agent (N6L) as an antitumor agent was successfully loaded onto LPMS microspheres. Interestingly, the resulting particles showed pore-size-dependent anticancer activity with inhibition of cancer cell growth up to 60%.

Aerosol classification by dielectrophoresis: a theoretical study on spherical particles.

The possibilities and limitations using dielectrophoresis (DEP) for the dry classification of spherical aerosol particles was evaluated at low concentrations in a theoretical study. For an instrument with the geometry of concentric cylinders (similar to cylindrical DMA), the dependencies of target particle diameter [Formula: see text], resolution, and yield of the DEP classification on residence time, applied electric field strength, and pressure of the carrier gas were investigated. Further, the diffusion influence on the classification was considered. It was found that [Formula: see text] scales with the mean gas flow velocity [Formula: see text], classifier length L, and electric field strength E as [Formula: see text]. The resolution of the classification depends on the particle diameter and scales proportionally to [Formula: see text]. It is constrained by the flow ratio [Formula: see text] (i.e., sheath gas to aerosol flow), electrode diameters, and applied electric field strength. The classification yield increases with the ratio of the width of the extended outlet slit [Formula: see text] to the diffusion induced broadening [Formula: see text]. As expected, resolution and yield exhibit opposite dependencies on [Formula: see text]. Our simulations show that DEP classification can principally cover a highly interesting particle size range from 100 nm to [Formula: see text] while being directly particle size-selective and particle charge independent.

Aerosol-Assisted Synthesis of Tailor-Made Hollow Mesoporous Silica Microspheres for Controlled Release of Antibacterial and Anticancer Agents.

Hollow mesoporous silica microsphere (HMSM) particles are one of the most promising vehicles for efficient drug delivery owing to their large hollow interior cavity for drug loading and the permeable mesoporous shell for controlled drug release. Here, we report an easily controllable aerosol-based approach to produce HMSM particles by continuous spray-drying of colloidal silica nanoparticles and Eudragit/Triton X100 composite (EUT) nanospheres as templates, followed by template removal. Importantly, the internal structure of the hollow cavity and the external morphology and the porosity of the mesoporous shell can be tuned to a certain extent by adjusting the experimental conditions (i.e., silica to EUT mass ratio and particle size of silica nanoparticles) to optimize the drug loading capacity and the controlled-release properties. Then, the application of aerosol-synthesized HMSM particles in controlled drug delivery was investigated by loading amoxicillin as an antibiotic compound with high entrapment efficiency (up to 46%). Furthermore, to improve the biocompatibility of the amoxicillin-loaded HMSM particles, their surfaces were functionalized with poly(allylamine hydrochloride) and alginate as biocompatible polymers via the layer-by-layer assembly. The resulting particles were evaluated toward Escherichia coli (Gram-negative) bacteria and indicated the bacterial inhibition up to 90% in less than 2 h. Finally, we explored the versatility of HMSMs as drug carriers for pancreatic cancer treatment. Because the pH value of the extracellular medium in pancreatic tumors is lower than that of the healthy tissue, chitosan as a pH-sensitive gatekeeper was grafted to the HMSM surface and then loaded with a pro-apoptotic NCL antagonist agent (N6L) as an anticancer drug. The obtained particles exhibited pH-responsive drug releases and excellent anticancer activities with inhibition of cancer cell growth up to 60%.

Polysialic Acid-Mediated Activity Measurement of Polysialylated Recombinant Coagulation Factor VIII.

Measurement of modified biologic including coagulation factors with extended half-life obtained, for example, by polysialylation pose an analytical challenge especially if both biological activity and presence of modification have to be determined. Analytical methods applied so far address only 1 of the 2 quality attributes of modified biologics. Here, we describe the development and bioanalytical validation of a polysialic acid-mediated factor VIII activity assay: Polysialic acid-specific capture of polysialylated recombinant factor VIII is combined with a chromogenic FVIII activity test using commercially available reagents. This assay principle enabled measurement of FVIII activity down to the pico mole-range without any interference by nonmodified factor VIII. To the best of our knowledge, this is the first method to selectively, accurately, and precisely measure simultaneously activity and modification integrity of a polysialylated biologic in complex matrices, as shown by the bioanalytical validation data. The convenience, robustness, and reliability of using this method has been demonstrated by its application for the nonclinical development of the polysialylated recombinant FVIII preparation. The method principle could be applied to protein modifications other than polysialylation and to activity tests other than the chromogenic FVIII assay.

Evaluation of Factor VIII Polysialylation: Identification of a Longer-Acting Experimental Therapy in Mice and Monkeys.

Extended half-life (EHL) factor therapies are needed to reduce the burden of prophylaxis and improve treatment adherence in patients with hemophilia. BAX 826 is a novel polysialylated full-length recombinant factor VIII [polysialyic acid (PSA) rFVIII] with improved pharmacokinetics (PK), prolonged pharmacology, and maintained safety attributes to enable longer-acting rFVIII therapy. In factor VIII (FVIII)-deficient hemophilic mice, PSArFVIII showed a substantially higher mean residence time (>2-fold) and exposure (>3-fold), and prolonged efficacy in tail-bleeding experiments (48 vs. 30 hours) compared with unmodified recombinant FVIII (rFVIII), as well as a potentially favorable immunogenicity profile. Reduced binding to a scavenger receptor (low-density lipoprotein receptor-related protein 1) and von Willebrand factor (VWF) as well as a largely VWF-independent circulation time in mice provide a rationale for prolonged BAX 826 activity. The significantly improved PK profile versus rFVIII was confirmed in cynomolgus monkeys [mean residence time: 23.4 vs. 10.1 hours; exposure (area under the curve from time 0 to infinity): 206 vs. 48.2 IU/ml⋅h] and is in line with results from rodent studies. Finally, safety and toxicity evaluations did not indicate increased thrombogenic potential, and repeated administration of BAX 826 to monkeys and rats was well tolerated. The favorable profile and mechanism of this novel experimental therapeutic demonstrated all of the requirements for an EHL-rFVIII candidate, and thus BAX 826 was entered into clinical assessment for the treatment of hemophilia A. SIGNIFICANCE STATEMENT: Prolongation of FVIII half-life aims to reduce the burden of prophylaxis and improve treatment outcomes in patients with hemophilia. This study shows that polysialylation of PSArFVIII resulted in prolongations of rFVIII circulation time and procoagulant activity, together with a favorable nonclinical safety profile of the experimental therapeutic.

Detection of Biologically Relevant Low-Titer Neutralizing Antibodies Against Adeno-Associated Virus Require Sensitive In Vitro Assays.

Patients with preexisting anti-adeno-associated virus serotype 8 (AAV8) neutralizing antibodies (NAbs) are currently excluded from AAV8 gene therapy trials. Therefore, the assessment of biologically relevant AAV8-NAb titers is critical for product development in gene therapy. However, standardized assays have not been routinely used to determine anti-AAV8-NAb titers, contributing to a wide range of reported anti-AAV8 prevalence rates. Using a clinical in vitro NAb assay in a separate study, a higher than expected anti-AAV8-NAb prevalence of about 50% was found in international cohorts. This comparative study has a translational character, confirming the biological relevance of anti-AAV8-antibody titers measured by this assay. The significance of low-titer anti-AAV8 NAbs is shown, along with the relevance of the in vitro assay cutoff (1:5) compared with other assays. Importantly, internally standardized reagents and purified AAV8 constructs containing 90% full capsids were used to reduce the effect of empty capsids. It was found that even very low anti-AAV8-NAb titers (<1:5) could efficiently hinder transduction in vivo, demonstrating the importance of sensitive NAb assays for clinical applications. The in vitro NAb assay was found to be more sensitive than an in vivo NAb assay and thus more suitable for patient screening. Additionally, the study showed that anti-AAV8-NAb titers <1:5 were very rare, further supporting the in vitro assay. However, assays using a lower cutoff may still be useful to explain potential variances in transgene expression. These findings support the relevance of the higher than expected prevalence of anti-AAV8 NAbs, highlighting the need for strategies to circumvent preexisting anti-AAV8 NAbs.

IVIG induces apoptotic cell death in CD56dim NK cells resulting in inhibition of ADCC effector activity of human PBMC.

The mechanism of the efficacy of Intravenous immunoglobulins (IVIG) in autoimmune and inflammatory diseases is not well understood. This study aimed at understanding mechanisms of IVIG-mediated suppression of effector cell activities of peripheral blood mononuclear cells (PBMC) in antibody-dependent cellular cytotoxicity (ADCC). We were particularly interested in CD56dim NK cells, the main ADCC effector cells in PBMC. Exposure of PBMC to IVIG for at least 48 h induced a caspase-3-dependent apoptotic cell death of CD56dim NK cells without affecting CD56bright NK cells. Induction of apoptosis in CD56dim NK cells and concomitant suppression of ADCC effector activities of PBMC was associated with the monomer fraction of IVIG. Moreover, it was independent of IgG sialyation, did not depend on engagement of FcγRIII and could not be mimicked by IVIG (Fab')2 or IVIG Fc preparations. The described effect could contribute to the reduction of peripheral NK cells observed during IVIG therapy in patients.

Characterization and Applications of Nanoparticles Modified in-Flight with Silica or Silica-Organic Coatings.

Nanoparticles are coated in-flight with a plasma-enhanced chemical vapor deposition (PECVD) process at ambient or elevated temperatures (up to 300 °C). Two silicon precursors, tetraethyl orthosilicate (TEOS) and hexamethyldisiloxane (HMDSO), are used to produce inorganic silica or silica-organic shells on Pt, Au and TiO2 particles. The morphology of the coated particles is examined with transmission electron microscopy (TEM) and the chemical composition is studied with Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). It is found that both the precursor and certain core materials have an influence on the coating composition, while other parameters, such as the precursor concentration, aerosol residence time and temperature, influence the morphology, but hardly the chemical composition. The coated particles are used to demonstrate simple applications, such as the modification of the surface wettability of powders and the improvement or hampering of the photocatalytic activity of titania particles.

Development of Methods for the Selective Measurement of the Single Amino Acid Exchange Variant Coagulation Factor IX Padua.

The description of hyper-functional factor IX (FIX) Padua triggered the development of BAX 335, an AAV8-based hemophilia B gene therapy vector designed to compensate for low FIX protein expression levels by expressing the FIX Padua variant, thereby reducing the exposure to viral vector. The presence of inactive FIX protein at baseline hindered conventional FIX:Ag ELISA from contributing to a more profound understanding of clinical data from the BAX 335 Phase 1/2 study (ClinicalTrials.gov: NCT01687608). By applying phage display technology, a Fab2 mini-antibody selectively binding to FIX Padua was developed and used to establish a FIX Padua-specific ELISA. The assay adequately performed, utilizing human and monkey plasma samples, and enabled the selective quantification of FIX Padua protein in human plasma samples from the BAX 335 trial. The mini-antibody also allowed the development of a chromogenic FIX Padua-specific activity assay, which adequately performed in human and mouse plasma. Collectively, the isolated FIX Padua-specific mini-antibody enabled the development of transgene-product-specific assays, which should improve the monitoring of hemophilia B gene therapies. The approach applied here for FIX Padua could be leveraged to develop variant-specific activity assays for other therapies where highly active enzymes are instrumental in achieving therapeutic levels of the transgene product.