IgG antibodies against bovine serum albumin in humans--their prevalence and response to exposure to bovine serum albumin

Differentiating Induced Pluripotent Stem Cells into Natural Killer Cells for Adoptive Cell Immunotherapies-Comparative Characterization of Current Protocols

Cancers constitute a leading cause of mortality. Chimeric antigen receptor (CAR) cell therapies provide breakthrough solutions for various cancers while posing considerable risks of immunological side reactions. Of various cytotoxic lymphocyte subsets, natural killer (NK) cells are considered the least immunogenic. Obtaining viable NK cells with stable phenotypes in quantities sufficient for modification is technologically challenging. The candidate sources include primary mononuclear cell cultures and immortalized NK cell lines; alternatively, the clinical-grade NK cells can be differentiated from induced pluripotent stem cells (iPSCs) by a good manufacturing practice (GMP)-compatible xeno-free protocol. In this review, we analyze existing protocols for targeted differentiation of human iPSCs into NK cells with a focus on xeno-free requirements.

Deciphering Saquinavir-Bovine Serum Albumin Interactions: Spectroscopic and Computational Insights

Bovine serum albumin (BSA) plays a crucial role as a carrier protein in plasma, binding various ligands, including drugs. Understanding the interaction between BSA and saquinavir, an antiretroviral drug, is essential for predicting its pharmacokinetics and pharmacodynamics. We employed spectroscopic approaches, including circular dichroism spectrometry and fluorescence spectroscopy, to investigate the binding of saquinavir to BSA. CD studies revealed conformational changes upon saquinavir mesylate binding, and the complex was stable up to 45°C during thermal denaturation. Saquinavir quenched the intrinsic fluorescence of BSA, indicating static quenching due to complex formation. Additionally, molecular docking simulations were performed to elucidate the favored binding site and interactions. The molecular docking results revealed that Subdomains IIA and IIB, which are proximal to Sudlow Site I, are the principal binding sites for the antiviral drug saquinavir. The ligand-bound pose of BSA also revealed that residue Trp213, which is adjacent to saquinavir, further validated the results of the fluorescence quenching assay, suggesting that residue Trp213 is quenched upon binding with saquinavir. MD simulations allowed us to explore the dynamic behavior of the BSA-saquinavir complex over time. We observed conformational fluctuations, solvent exposure, flexibility of binding pockets, free energy landscape, and binding energy. This study enhances our understanding of drug-protein interactions and contributes to drug development and optimization.

Comparison of Drug Delivery Systems with Different Types of Nanoparticles in Terms of Cellular Uptake and Responses in Human Endothelial Cells, Pericytes, and Astrocytes

Background/Objectives: The key components of the blood-brain barrier (BBB) are endothelial cells, pericytes, astrocytes, and the capillary basement membrane. The BBB serves as the main barrier for drug delivery to the brain and is the most restrictive endothelial barrier in the body. Nearly all large therapeutic molecules and over 90% of small-molecule drugs cannot cross the BBB. To overcome this challenge, nanotechnology, particularly drug delivery systems such as nanoparticles (NPs), have gained significant attention. Methods: Poly(lactide-co-glycolide) (PLGA) and albumin-based NPs (bovine/human), with or without transferrin (Tf) ligands (BSA, HSA, BSA-Tf, HSA-Tf), and nanolipid carriers (NLC) were synthesized. The interactions of these NPs with human brain microvascular endothelial cells (hBMECs), human brain vascular pericytes (hBVPs), and human astrocytes (hASTROs) were analyzed. Results: At doses of 15.62 µg/mL, 31.25 µg/mL, and 62.5 µg/mL, none of the NPs caused toxic effects on hBMECs, hBVPs, or hASTROs after 3 h of incubation. All NPs were internalized by the cells, but BSA-Tf and HSA-Tf showed significantly higher uptake in hBMECs in a dose-dependent manner. Ultrastructural analysis revealed notable differences between NP formulation and cell type. Conclusions: Our findings underscore the potential of ligand-targeted NPs to selectively interact with BBB endothelial cells. Ultrastructural analysis reveals distinct cellular processing pathways for various NP formulations across BBB-associated cell types, with autophagy emerging as a crucial mechanism for NP handling in pericytes and astrocytes. Changes in NP chemical properties upon biological exposure present significant challenges for nanomedicine design, emphasizing the need for further investigation into NP interactions at the cellular and subcellular levels.

Polyaniline-based bovine serum albumin imprinted electrochemical sensor for ultra-trace-level detection in clinical and food safety applications

Monitoring bovine serum albumin (BSA) at ultra-low levels is crucial for clinical and food safety applications, as it plays a significant role in identifying various health conditions and potential risks, necessitating fast, trace-level detection of BSA. This study proposes an approach to address these challenges by employing molecularly imprinted polymer (MIP) to develop an ultra-trace-level and cost-effective BSA sensing platform. The MIP electrochemical sensor was developed using polyaniline (PANI) combined with the protein crosslinker glutaraldehyde (GA) to optimize BSA surface imprinting in the MIP. As a result, the sensor achieves a sensitivity of 1.24 μA/log(pg/mL), with a picomolar detectable limit of 2.3 pg/mL (0.035 pM) and a wide detection range from 20 pg/mL to 200,000 pg/mL (0.303 pM to 3030 pM), making it suitable for clinical and food safety applications. Additionally, the study explores the interaction between an acidic surfactant protein eluent (acetic acid with sodium dodecyl sulfate, AcOH-SDS) and BSA vacant sites, enhancing recognition and re-binding. The PANI-based MIP sensor demonstrates initial feasibility and practicality in commercial milk and real human serum, opening avenues for early disease detection and ensuring food safety in BSA-related immune responses.

False-positive Serum Antiglomerular Basement Membrane Antibody due to Bovine Serum Albumin-containing Surgical Adhesive: A Case Report

Antiglomerular basement membrane (GBM) disease has a poor prognosis. The rapid detection of serum anti-GBM antibody using an enzyme immunoassay, which has a high sensitivity and specificity, leads to an early diagnosis and improved prognosis. We report a case of acute kidney injury with false-positive anti-GBM antibody. A man in his early fifties underwent aortic arch replacement using bovine serum albumin (BSA)-containing surgical adhesion. After intravenous administration of vancomycin for a fever, he developed acute kidney injury without an abnormal urinalysis, and his anti-GBM antibody titer (fluorescence enzyme immunoassay [FEIA]) was 70.4 IU/mL. A kidney biopsy showed acute tubular injury and minor glomerular abnormalities without immunoglobulin G deposits, suggesting no evidence of anti-GBM glomerulonephritis. Consistent with the false-positive anti-GBM antibody test results, anti-GBM antibody determined using a chemiluminescent enzyme immunoassay was negative. A serum sample showed crossbinding to the FEIA plate from which the GBM antigen was removed. This finding indicated a nonspecific reaction to BSA, which contains a coating solution for the FEIA plate. This reaction was likely caused by anti-BSA antibody produced using BSA-containing surgical adhesion. Our findings suggest emerging challenges in diagnosing anti-GBM disease. Nephrologists must remain vigilant regarding false-positive anti-GBM antibody test results, particularly in cases evaluated with immunoassays that contain BSA.

New synthesis of oligosaccharides modelling the M epitope of the Brucella O-polysaccharide

Brucellosis is a dangerous zoonotic disease caused by bacteria of the genus Brucella. Diagnosis of brucellosis is based on the detection in animal and human sera of antibodies to the O-polysaccharide of Brucella lipopolysaccharide. The currently employed serodiagnosis of brucellosis relies on the use of the Brucella O-polysaccharide as a diagnostic antigen. However, the existence of bacterial species, which also express O-polysaccharides structurally similar to that of Brucella, may decrease the specificity of the brucellosis detection due to false-positive test results. It has been shown that the efficiency of the test can be significantly improved by using synthetic oligosaccharides that correspond to the so-called M epitope of the Brucella O-antigen. This epitope is characterized by an α-(1→3)-linkage between d-perosamine units and is unique to Brucella. Here we report on an efficient approach to the synthesis of oligosaccharides that model the M epitope of the Brucella O-polysaccharide. The approach is based on the use of the α-(1→3)-linked disaccharide thioglycoside as the key donor block. Its application allowed the straightforward assembly of a set of four protected oligosaccharides, which includes a disaccharide, two trisaccharides, and a tetrasaccharide, in five glycosylation steps. The synthesized oligosaccharides are planned to be used in the development of diagnostic tools for identifying brucellosis in humans and domestic animals, as well as a potential vaccine against it.

HSA over BSA: Selective detection of Human Serum Albumin via a naphtho [2,1-b] furan-based system

Human serum albumin (HSA) is an important biomarker that can be used for the early diagnosis of many diseases. In this work, a TICT probe bearing fused naphtho-furan scaffold (NPNF) was developed and employed in the selective turn-on sensing of HSA. The probe's selectivity towards HSA was observed using steady-state fluorescence experiments, with limit of quantitation in micromolar levels. NPNF's capability to exclusively detect HSA over BSA was further studied/rationalized using anisotropy and time-resolved studies. Molecular docking was used to shed light on the location of NPNF in the subdomain IB of HSA. The practical application of the probe was also demonstrated by the detection of HSA in urine and the HSA-assisted detection of cerium.

A novel test for type-I allergy based on crosslink formation of immunoglobulin-E receptors by allergen-specific immunoglobulin-E antibodies and an allergen

Detection of allergen-specific immunoglobulin E (IgE) antibodies (Abs) in serum would allow for screening of the causative allergen in patients with type-I allergy. In this study, we developed a new assay method to detect allergen-specific IgE Abs, which involved crosslinking the plural FcεRIα molecules with an allergen and detection using an amplified luminescence proximity homogeneous assay (AlphaCL). First, the allergen concentration, bead concentrations, and incubation time were optimized for the detection of anti-2,4-dinitrophenyl (DNP) IgE Abs in buffer. Under optimal conditions, AlphaCL was able to detect DNP-specific IgE Abs in simulated human serum at levels comparable to those in serum from type-I allergic patients. When AlphaCL was used to detect anti-DNP IgE Abs, no signal counts were obtained with the monovalent allergen 2,4-dinitrophenylated poly-γ-glutamic acid, whereas high signal counts were obtained with the multivalent allergen DNP-BSA. This confirmed that AlphaCL could specifically detect allergen-specific IgE Abs with the ability to crosslink a multivalent allergen. In summary, we have established a new assay model using AlphaCL to detect allergen-specific IgE Abs with FcεRIα crosslinking ability in human serum. This simple and practical assay model may be applied as a new diagnostic tool for patients with type-I allergy.

Protein-based Nanoparticles: From Drug Delivery to Imaging, Nanocatalysis and Protein Therapy

Proteins and enzymes are versatile biomaterials for a wide range of medical applications due to their high specificity for receptors and substrates, high degradability, low toxicity, and overall good biocompatibility. Protein nanoparticles are formed by the arrangement of several native or modified proteins into nanometer-sized assemblies. In this review, we will focus on artificial nanoparticle systems, where proteins are the main structural element and not just an encapsulated payload. While under natural conditions, only certain proteins form defined aggregates and nanoparticles, chemical modifications or a change in the physical environment can further extend the pool of available building blocks. This allows the assembly of many globular proteins and even enzymes. These advances in preparation methods led to the emergence of new generations of nanosystems that extend beyond transport vehicles to diverse applications, from multifunctional drug delivery to imaging, nanocatalysis and protein therapy.

Local, systemic and immunologic safety comparison between xenogeneic equine umbilical cord mesenchymal stem cells, allogeneic canine adipose mesenchymal stem cells and placebo: a randomized controlled trial

Mesenchymal stem cells are multipotent cells with a wide range of therapeutic applications, including, among others, tissue regeneration. This work aims to test the safety (EUC-MSC) of intra-articular administration of equine umbilical cord mesenchymal stem cells in young healthy dogs under field conditions following single and repeated administration. This was compared with the safety profile of allogenic canine adipose derived mesenchymal stem cells (CAD-MSC) and placebo in order to define the safety of xenogeneic use of mesenchymal stem cells when administered intra-articular. Twenty-four police working dogs were randomized in three groups in a proportion 1:1:1. EUC-MSCs and CAD-MSCs were obtained from healthy donors and were manufactured following company SOPs and under GMP and GMP-like conditions, respectively, and compliant all necessary controls to ensure the quality of the treatment. The safety of the treatment was evaluated locally, systemically and immunologically. For this purpose, an orthopedic examination and Glasgow test for the assessment of pain in the infiltrated joint, blood tests, clinical examination and analysis of the humoral and cellular response to treatment were performed. No adverse events were detected following single and repeated MSC administration despite both equine and canine MSC generate antibody titres in the dogs. The intra-articular administration of equine umbilical cord mesenchymal stem cells in dogs has demonstrated to be safe.

Composition, host responses and clinical applications of bioadhesives

Bioadhesives are medical devices used to join or seal tissues that have been injured or incised. They have been classified into tissue adhesives, sealants, and hemostatic agents. Bioadhesives such as FloSeal®, CoSeal®, BioGlue®, Evicel®, Tisseel®, Progel™ PALS, and TissuGlu® have been commercialized and used in clinical setting. They can be formulated with natural or synthetic components or a combination of both including albumin, glutaraldehyde, chitosan, cyanoacrylate, fibrin and thrombin, gelatin, polyethylene glycol (PEG), along with urethanes. Each formulation has intrinsic properties and has been developed and validated for a specific application. This review article briefs the mechanisms by which bioadhesives forms adhesion to tissues and highlights the correlation between bioadhesives composition and their potential host responses. Furthermore, clinical applications of bioadhesives and their application-driven requirements are outlined.

The Uniqueness of Albumin as a Carrier in Nanodrug Delivery

Albumin is an appealing carrier in nanomedicine because of its unique features. First, it is the most abundant protein in plasma, endowing high biocompatibility, biodegradability, nonimmunogenicity, and safety for its clinical application. Second, albumin chemical structure and conformation allows interaction with many different drugs, potentially protecting them from elimination and metabolism in vivo, thus improving their pharmacokinetic properties. Finally, albumin can interact with receptors overexpressed in many diseased tissues and cells, providing a unique feature for active targeting of the disease site without the addition of specific ligands to the nanocarrier. For this reason, albumin, characterized by an extended serum half-life of around 19 days, has the potential of promoting half-life extension and targeted delivery of drugs. Therefore, this article focuses on the importance of albumin as a nanodrug delivery carrier for hydrophobic drugs, taking advantage of the passive as well as active targeting potential of this nanocarrier. Particular attention is paid to the breakthrough NAB-Technology, with emphasis on the advantages of Nab-Paclitaxel (Abraxane), compared to the solvent-based formulations of Paclitaxel, i.e., CrEL-paclitaxel (Taxol) in a clinical setting. Finally, the role of albumin in carrying anticancer compounds is depicted, with a particular focus on the albumin-based formulations that are currently undergoing clinical trials. The article sheds light on the power of an endogenous substance, such as albumin, as a drug delivery system, signifies the importance of the drug vehicle in drug performance in the biological systems, and highlights the possible future trends in the use of this drug delivery system.

Circulating antibodies against age-modified proteins in patients with coronary atherosclerosis

Advanced glycation endproducts (AGEs) are formed in a series of non-enzymatic reactions between reducing sugars and the amino groups of proteins and accumulate during aging, diabetes mellitus, chronic kidney disease and other chronic diseases. Accumulation of AGE-modifications alters protein structure and function, transforming these molecules into potential targets of the immune system, presumably triggering the production of autoantibodies against AGEs. In this study, we detected autoantibodies against AGE-modified proteins with ELISA in plasma samples of 91 patients with documented coronary artery disease (CAD), who underwent coronary artery bypass grafting (CABG) surgery. Patients with high levels of autoantibodies had a higher body mass index (BMI 28.6 vs 27.1 kg/m²; p = 0.046), were more likely to suffer from chronic obstructive pulmonary disease (COPD 30% vs 9.8%; p = 0.018), and more likely to need dialysis after the surgery (10% vs 0%; p = 0.037). Our findings show a weak link between the levels of autoantibodies against AGEs and diabetes mellitus (DM 44% vs 24.4%; p = 0.05). In a small subpopulation of patients, antibodies against native bovine serum albumin (BSA) were detected. A growing body of research explores the potential role of antibodies against AGE-modified proteins in pathogenesis of different chronic diseases; our data confirms the presence of AGE-autoantibodies in patients with CAD and that in parallel to the AGEs themselves, they may have a potential role in concomitant clinical conditions in patients undergoing CABG surgery. Further research is necessary to verify the molecular role of these antibodies in different pathological conditions.

Formation of three-dimensional tubular endothelial cell networks under defined serum-free cell culture conditions in human collagen hydrogels

Implementation of tubular endothelial cell networks is a prerequisite for 3D tissue engineering of constructs with clinically relevant size as nourishment of cells is challenged by the diffusion limit. In vitro generation of 3D networks is often achieved under conditions using serum containing cell culture medium and/or animal derived matrices. Here, 3D endothelial cell networks were generated by using human umbilical vein endothelial cells (HUVECs) in combination with human adipose tissue derived stromal cells (hASCs) employing human collagen I as hydrogel and decellularized porcine small intestinal submucosa as starter matrix. Matrigel/rat tail collagen I hydrogel was used as control. Resulting constructs were cultivated either in serum-free medium or in endothelial growth medium-2 serving as control. Endothelial cell networks were quantified, tested for lumen formation, and interaction of HUVECs and hASCs. Tube diameter was slightly larger in constructs containing human collagen I compared to Matrigel/rat tail collagen I constructs under serum-free conditions. All other network parameters were mostly similar. Thereby, the feasibility of generating 3D endothelial cell networks under serum-free culture conditions in human collagen I as hydrogel was demonstrated. In summary, the presented achievements pave the way for the generation of clinical applicable constructs.

The development of induced pluripotent stem cell-derived mesenchymal stem/stromal cells from normal human and RDEB epidermal keratinocytes

BACKGROUND

Epidermolysis bullosa (EB) is a group of hereditary disorders caused by mutations in the genes encoding structural molecules of the dermal-epidermal junction (DEJ). Cell-based therapies such as allogeneic mesenchymal stem/stromal cell (MSC) transplantation have recently been explored for severe EB types, such as recessive dystrophic EB (RDEB). However, hurdles exist in current MSC-based therapies, such as limited proliferation from a single cell source and limited cell survival due to potential allogenic rejection.

OBJECTIVES

We aimed to develop MSCs from keratinocyte-derived induced pluripotent stem cells (iPSCs).

METHODS

Keratinocyte-derived iPSCs (KC-iPSCs) of a healthy human and an RDEB patient were cultured with activin A, 6-bromoindirubin-3'-oxime and bone morphogenetic protein 4 to induce mesodermal lineage formation. These induced cells were subjected to immunohistochemical analysis, flow cytometric analysis and RNA microarray analysis in vitro, and were injected subcutaneously and intravenously to wounded immunodeficient mice to assess their wound-healing efficacy.

RESULTS

After their induction, KC-iPSC-induced cells were found to be compatible with MSCs. Furthermore, with the subcutaneous and intravenous injection of the KC-iPSC-induced cells into wounded immunodeficient mice, human type VII collagen was detected at the DEJ of epithelized areas.

CONCLUSIONS

We successfully established iPSC-derived MSCs from keratinocytes (KC-iPSC-MSCs) of a normal human and an RDEB patient. KC-iPSC-MSCs may have potential in therapies for RDEB.

Immunogenicity of glycans on biotherapeutic drugs produced in plant expression systems-The taliglucerase alfa story

Plants are a promising alternative for the production of biotherapeutics. Manufacturing in-planta adds plant specific glycans. To understand immunogenic potential of these glycans, we developed a validated method to detect plant specific glycan antibodies in human serum. Using this assay, low prevalence of pre-existing anti-plant glycan antibodies was found in healthy humans (13.5%) and in glucocerebrosidase-deficient Gaucher disease (GD) patients (5%). A low incidence (9% in naïve patient and none in treatment experienced patients) of induced anti-plant glycan antibodies was observed in GD patients after up to 30 months replacement therapy treatment with taliglucerase alfa, a version of human glucocerebrosidase produced in plant cells. Detailed evaluation of clinical safety and efficacy endpoints indicated that anti-plant glycan antibodies did not affect the safety or efficacy of taliglucerase alfa in patients. This study shows the benefit of using large scale human trials to evaluate the immunogenicity risk of plant derived glycans, and indicates no apparent risk related to anti-plant glycan antibodies.

Immunogenicity of decidual stromal cells in an epidermolysis bullosa patient and in allogeneic hematopoietic stem cell transplantation patients

Allogeneic mesenchymal stromal cells (MSCs) are widely used in regenerative medicine, but little is known about their immunogenicity. In this study, we monitored the therapeutic and immunogenic effects of decidual stromal cells (DSCs) from term placentas when used as a therapy for generalized severe junctional epidermolysis bullosa (JEB) (previously termed Herlitz JEB), a lethal condition caused by the lack of functional laminin-332. An 11-month-old JEB patient was treated with five infusions of allogeneic DSCs within a 3-month period. Amniotic membranes (AMs) were applied to severe wounds. After the treatment, wounds started to heal in the middle of the blisters, but the improvements were transient. After two infusions of DSCs, the JEB patient had developed multispecific anti-HLA class-I antibodies. No antibodies to laminin-332 were detected, but the patient had high levels of anti-bovine serum albumin antibodies, which could bind to DSCs. Peripheral blood mononuclear cells (PBMCs) from the patient had a higher proliferative response to DSCs than to third-party PBMCs, which contrasts with the pattern observed in healthy donors. Human DSCs and MSCs induced similar xenoreactivity in mice. Two of 16 allogeneic stem cell-transplanted patients, treated with DSCs for graft-versus-host disease or hemorrhagic cystitis, showed a positive flow cytometric crossmatch test. One patient had anti-HLA antibodies before DSC infusion, whereas the other had no anti-HLA antibodies at any time. AM and DSC infusions may have improved the healing process in the JEB patient, but DSCs appeared to induce anti-HLA antibodies. The risk of alloimmunization by DSCs seems to be low in immunocompromised patients.

Autoimmune profiling with protein microarrays in clinical applications

In recent years, knowledge about immune-related disorders has substantially increased, especially in the field of central nervous system (CNS) disorders. Recent innovations in protein-related microarray technology have enabled the analysis of interactions between numerous samples and up to 20,000 targets. Antibodies directed against ion channels, receptors and other synaptic proteins have been identified, and their causative roles in different disorders have been identified. Knowledge about immunological disorders is likely to expand further as more antibody targets are discovered. Therefore, protein microarrays may become an established tool for routine diagnostic procedures in the future. The identification of relevant target proteins requires the development of new strategies to handle and process vast quantities of data so that these data can be evaluated and correlated with relevant clinical issues, such as disease progression, clinical manifestations and prognostic factors. This review will mainly focus on new protein array technologies, which allow the processing of a large number of samples, and their various applications with a deeper insight into their potential use as diagnostic tools in neurodegenerative diseases and other diseases. This article is part of a Special Issue entitled: Biomarkers: A Proteomic Challenge.

Pore-forming compounds as signal transduction elements for highly sensitive biosensing

Pore-forming compounds are attracting much attention due to the signal transduction ability for the development of highly sensitive biosensing. In this review, we describe an overview of the recent advances made by our group in the design of molecular sensing interfaces of spherical and planar lipid bilayers and natural bilayers. The potential uses of pore-forming compounds, such as gramicidin and MCM-41, in lipid bilayers and natural glutamate receptor channels in biomembrane are presented.

Serology with ML Flow test in health professionals from three different states of Brazil

BACKGROUND

In highly endemic countries, transmission and sub-clinical infection of leprosy are likely and the disease manifests itself in individuals without any known close contact with a leprosy patient. Health workers are social contacts belonging to the same network (the Health System) and some of them share the same social environment (nursing assistants) as patients with known patients and / or carriers.

OBJECTIVE

To identify ML Flow seropositivity among health professionals.

METHODS

We conducted a cross-sectional study using a serological survey with the ML Flow test in 450 health professionals (doctors, nurses and nursing assistants), in order to detect seropositivity in areas of high and low endemicity in municipalities from three Brazilian states (RJ, MS and RS).

RESULTS

The results showed general 16% seropositivity, higher in low endemic areas, regardless of whether there was direct care for leprosy patients. Paradoxically, a statistical association was observed between the area studied and seropositivity, as the place with the lowest endemicity (CA) had the highest seropositivity rate (p = 0.033).

CONCLUSION

The authors suggest these results are associated with a presence of an unspecified link to bovine serum albumin (BSA), carrier of PGL-1 in the ML Flow test, and recommend expanded seroepidemiological research utilizing tests with human and bovine albumin.

Preparation of non-aggregated fluorescent nanodiamonds (FNDs) by non-covalent coating with a block copolymer and proteins for enhancement of intracellular uptake

Fluorescent nanodiamonds (FNDs) are very promising fluorophores for use in biosystems due to their high biocompatibility and photostability. To overcome their tendency to aggregate in physiological solutions, which severely limits the biological applications of FNDs, we developed a new non-covalent coating method using a block copolymer, PEG-b-P(DMAEMA-co-BMA), or proteins such as BSA and HSA. By simple mixing of the block copolymer with FNDs, the cationic DMAEMA and hydrophobic BMA moieties can strongly interact with the anionic and hydrophobic moieties on the FND surface, while the PEG block can form a shell to prevent the direct contact between FNDs. The polymer-coated FNDs, along with BSA- and HSA-coated FNDs, showed non-aggregation characteristics and maintained their size at the physiological salt concentration. The well-dispersed, polymer- or protein-coated FNDs in physiological solutions showed enhanced intracellular uptake, which was confirmed by CLSM. In addition, the biocompatibility of the coated FNDs was expressly supported by a cytotoxicity assay. Our simple non-covalent coating with the block copolymer, which can be easily modified by various chemical methods, projects a very promising outlook for future biomedical applications, especially in comparison with covalent coating or protein-based coating.

[Pathophysiology of extramembranous glomerulopathies. Fifty years of progress, from laboratory to patient]

Membranous nephropathy (MN) is a kidney disease characterized by deposition of immune complexes and complement on the outer aspect of the glomerular capillary wall. It is responsible for a loss of serum proteins in the urine and kidney failure. During the last ten years, considerable progress has occurred in the understanding of the molecular bases of the disease with the description of three distinct mechanisms in humans. In the neonatal allo-immune form, antibodies are directed against neutral endopeptidase (NEP), a podocyte antigen absent in the mothers who become immunized against this antigen expressed by placenta cells during pregnancy. NEP was the first podocyte antigen to be identified in MN. Most adult forms of MN are autoimmune diseases without identified etiology (primary MN), linked to the production of antibodies raised against another podocyte antigen, the type-M phospholipase A2 receptor (PLA2R1). Anti-PLA2R1 antibodies are detected in 70 to 80% of patients before any immunosuppressive treatment, and only occasionally in secondary forms of MN, variants of PLAR1 and HLA-DQA1 genes are very significantly associated with occurrence of primary MN in Caucasians. The third mechanism is characterized by immunization against a foreign protein, cationic bovine serum albumin (BSA), which is involved in rare forms of MN during early childhood. This finding points to a possible role of food and environmental antigens in membranous nephropathy.

Structures of bovine, equine and leporine serum albumin

Serum albumin first appeared in early vertebrates and is present in the plasma of all mammals. Its canonical structure supported by a conserved set of disulfide bridges is maintained in all mammalian serum albumins and any changes in sequence are highly correlated with evolution of the species. Previous structural investigations of mammalian serum albumins have only concentrated on human serum albumin (HSA), most likely as a consequence of crystallization and diffraction difficulties. Here, the crystal structures of serum albumins isolated from bovine, equine and leporine blood plasma are reported. The structure of bovine serum albumin (BSA) was determined at 2.47 Å resolution, two crystal structures of equine serum albumin (ESA) were determined at resolutions of 2.32 and 2.04 Å, and that of leporine serum albumin (LSA) was determined at 2.27 Å resolution. These structures were compared in detail with the structure of HSA. The ligand-binding pockets in BSA, ESA and LSA revealed different amino-acid compositions and conformations in comparison to HSA in some cases; however, much more significant differences were observed on the surface of the molecules. BSA, which is one of the most extensively utilized proteins in laboratory practice and is used as an HSA substitute in many experiments, exhibits only 75.8% identity compared with HSA. The higher resolution crystal structure of ESA highlights the binding properties of this protein because it includes several bound compounds from the crystallization solution that provide additional structural information about potential ligand-binding pockets.

Membranous nephropathy: the start of a paradigm shift

PURPOSE OF REVIEW

Primary membranous nephropathy is a common glomerular disease characterized by sub-epithelial immune deposits that has become the prototype of an autoimmune glomerular disease. The purpose of this review is to highlight recent advances regarding the pathogenesis of membranous nephropathy as well as potential new therapies.

RECENT FINDINGS

The discovery of two major podocyte antigens, neutral endopeptidase (NEP), involved in rare cases of neonatal membranous nephropathy, and the M-type phospholipase A2 receptor 1 (PLA2R1), the first antigen discovered in adults, have been major 'breakthroughs' in our understanding of the pathogenesis of human membranous nephropathy. Anti-PLA2R antibodies appear to predict activity of the disease as well as response to therapy. Pediatric and adult cases of membranous nephropathy occurring in the presence of circulating cationic bovine serum album (BSA) and anti-BSA antibodies have also been described, raising the possibility that food antigens may be involved in the development of membranous nephropathy. Moreover, the results of genetic susceptibility have become available. Exciting progress has also been made in the treatment of this disease including therapy with adrenocorticotropic hormone and rituximab.

SUMMARY

Understanding disease pathogenesis is crucial in guiding patient evaluation and designing appropriate therapy. Recent discoveries have helped to elucidate the pathophysiology of membranous nephropathy and may facilitate a more patient-specific treatment approach in these patients.

High prevalence of autoantibodies to C-reactive protein in patients with chronic hepatitis C infection: association with liver fibrosis and portal inflammation

The presence of autoantibodies against C-reactive protein (anti-CRP) has been reported in association with autoimmunity and histopathology in chronic hepatitis C virus (HCV) infection. Resistin could play a role in the pathogenesis of hepatitis, although results on HCV infection are ambiguous. Here we retrospectively analyzed anti-CRP and resistin levels in the sera of 38 untreated and well-characterized HCV patients at the time of their first liver biopsy. HCV activity and general health were assessed by a physician at least yearly until follow-up ended. Anti-CRP and resistin were also measured in patients with autoimmune hepatitis (AIH) and nonalcoholic fatty liver disease (NAFLD). Anti-CRP antibodies were registered in all HCV patients, whereas only a few AIH (11%) and NAFLD (12%) sera were positive. Anti-CRP levels were related to histopathological severity and were highest in patients with cirrhosis at baseline. Resistin levels were similar in HCV, AIH, and NAFLD patients, but high levels of resistin were associated with early mortality in HCV patients. Neither anti-CRP nor resistin predicted a response to interferon-based therapy or cirrhosis development or was associated with liver-related mortality. We conclude that anti-CRP antibodies are frequently observed in chronic HCV infection and could be a useful marker of advanced fibrosis and portal inflammation.

[Idiopathic and secondary membranous nephropathies]

Antibodies to neutral endopeptidase, a podocyte protein, are responsible for rare alloimmune neonatal membranous nephropathy that develops in children from neutral endopeptidase-deficient mothers. Neutral endopeptidase was the first podocyte antigen described in human membranous nephropathy. PLA2R1, the type-M receptor of soluble phospholipase A2, is a major target antigen in so-called idiopathic membranous nephropathy in adults. Antibodies to PLA2R1 are detected in 60 to 80% of patients before immunosuppressive treatment, and are only occasionally found in secondary membranous nephropathy. To date, they have not been detected in other pathological conditions and in healthy individuals. PLA2R1 and HLA-DQA1 gene variants defined by single nucleotide polymorphisms are strongly associated with idiopathic membranous nephropathy in patients of white ancestry, and can thus be considered as predisposing genes. In addition to their diagnostic value, anti-PLA2R1 antibodies can be used to monitor treatment. Immunization against cationic bovine serum albumin is a cause of early childhood membranous nephropathy. This finding points to a possible role of food and environmental antigens in membranous nephropathy. The newly identified antigen-antibody systems should be considered as molecular signatures challenging the uniform histological definition and having a major impact on patient care in a near future.

Advances in membranous nephropathy: success stories of a long journey

1. embranous nephropathy is characterized by an accumulation of immune deposits on the outer aspect of the glomerular basement membrane. 2. In the rat model described by Heymann in 1959, the target antigen of antibodies is megalin, a multiligand receptor expressed in the rat glomerulus but absent from the human glomerulus. 3. In recent years, two major antigens have been identified in human membranous nephropathy (MN). The first is neutral endopeptidase (NEP), the alloantigen involved in neonatal cases of MN that occur in newborns from NEP-deficient mothers. The second is the M-type phospholipase A(2) receptor (PLA(2) R), the first autoantigen identified in idiopathic MN in the adult. Megalin, NEP and PLA(2) R are all expressed on the podocyte surface, where they can serve as targets for circulating antibodies, leading to in situ immune complex formation, complement activation and proteinuria. 4. In addition to podocyte antigens, we recently showed that some patients with childhood MN had both circulating cationic bovine serum albumin (BSA) and anti-BSA antibodies, with BSA being present in immune deposits. This suggests that food antigens may be involved in MN through charge-dependent binding to the anionic glomerular capillary wall and in situ formation of immune complexes.

The evolution of vascular tissue engineering and current state of the art

Dacron® (polyethylene terephthalate) and Goretex® (expanded polytetrafluoroethylene) vascular grafts have been very successful in replacing obstructed blood vessels of large and medium diameters. However, as diameters decrease below 6 mm, these grafts are clearly outperformed by transposed autologous veins and, particularly, arteries. With approximately 8 million individuals with peripheral arterial disease, over 500,000 patients diagnosed with end-stage renal disease, and over 250,000 patients per year undergoing coronary bypass in the USA alone, there is a critical clinical need for a functional small-diameter conduit [Lloyd-Jones et al., Circulation 2010;121:e46-e215]. Over the last decade, we have witnessed a dramatic paradigm shift in cardiovascular tissue engineering that has driven the field away from biomaterial-focused approaches and towards more biology-driven strategies. In this article, we review the preclinical and clinical efforts in the quest for a tissue-engineered blood vessel that is free of permanent synthetic scaffolds but has the mechanical strength to become a successful arterial graft. Special emphasis is given to the tissue engineering by self-assembly (TESA) approach, which has been the only one to reach clinical trials for applications under arterial pressure.

Surface Plasmon Resonance imaging-based sensing for anti-bovine immunoglobulins detection in human milk and serum

Only few papers deal with Surface Plasmon Resonance imaging (SPRi) direct detection on complex matrices, limiting the biosensor application to real analytical problems. In this work a SPRi biosensor for anti-bovine IgG detection in untreated human bodily fluids, i.e. diluted human serum and milk, was developed. Enhanced levels of cow's milk antibodies in children's serum are suspected for their possible correlation with Type 1 diabetes during childhood and their detection in real samples was up to now performed by classical immunoassays based on indirect detection. The biosensor was optimised in standard samples and then in untreated human milk for anti-bovine IgG direct detection. The key novelty of the work is the evaluation of matrix effect by applying to real samples an experimental and ex ante method previously developed for SPRi signal sampling in standard solutions, called "Data Analyzer"; it punctually visualises and analyses the behaviour of receptor spots of the array, to select only spot areas with the best specific vs. unspecific signal values. In this way, benefits provide by SPRi image analysis are exploited here to quantify and minimise drawbacks due to the matrix effect, allowing to by-pass every matrix pre-treatment except dilution.

Effective in vitro expansion of CD40-activated human B lymphocytes in a defined bovine protein-free medium

CD40-CD154 interaction is used to culture human B lymphocytes, which are now viewed as effectors to potentially promote T lymphocyte response against malignant cells in cell-based therapy. Currently, the media used, based on bovine serum, are raising concerns for patient safety in such therapy. In this study, we have investigated whether human B lymphocytes could be cultured in the absence of bovine serum. Blood CD19(+) B lymphocytes were activated using interaction through CD40 in medium containing defined animals or human proteins and lipids, and were monitored during short-term periods (≤15 days). Conventional stem-cell medium and a medium containing human albumin instead of bovine albumin were tested. We observed that the response of B lymphocytes appeared influenced by lot-to-lot variability in low density lipoproteins (LDL). Nevertheless, B lymphocyte proliferation and secretion in serum-free and bovine protein-free media were quite similar to that of cells cultured in medium containing FBS. Our results show that CD40-activated B lymphocytes can be cultured for up to 15 days in a serum-free medium containing human albumin, LDL, α-tocopherol and chemically-defined lipids.

Early-childhood membranous nephropathy due to cationic bovine serum albumin

BACKGROUND

The M-type phospholipase A(2) receptor (PLA(2)R) was recently identified as a candidate antigen in 70% of cases of idiopathic membranous nephropathy, a common form of the nephrotic syndrome. The nature of antigens involved in other idiopathic and secondary membranous nephropathies remains unclear.

METHODS

We searched for antibodies against bovine serum albumin and circulating bovine serum albumin by means of enzyme-linked immunosorbent assay and Western blotting in serum specimens obtained from 50 patients with membranous nephropathy and 172 controls. The properties of immunopurified circulating bovine serum albumin obtained from serum specimens were analyzed with the use of two-dimensional sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. We detected bovine serum albumin in glomerular deposits and analyzed the reactivity of eluted IgG.

RESULTS

Eleven patients, including four children, had high levels of circulating anti-bovine serum albumin antibodies, of both the IgG1 and IgG4 subclasses. These patients also had elevated levels of circulating bovine serum albumin, without an increase in circulating immune complex levels. Bovine serum albumin immunopurified from the serum specimens of these four children migrated in the basic range of pH, whereas the bovine serum albumin from adult patients migrated in neutral regions as native bovine serum albumin. Bovine serum albumin was detected in subepithelial immune deposits only in the children with both high levels of cationic circulating bovine serum albumin and bovine serum albumin-specific antibodies, and it colocalized with IgG in the absence of PLA(2)R. IgG eluted from such deposits was specific for bovine serum albumin.

CONCLUSIONS

Some patients with childhood membranous nephropathy have both circulating cationic bovine serum albumin and anti-bovine serum albumin antibodies. Bovine serum albumin is present in immune deposits, suggesting that cationic bovine serum albumin is pathogenic through binding to the anionic glomerular capillary wall and in situ formation of immune complexes, as shown in experimental models.

Beware of Antibodies to Dietary Proteins in “Antigen-specific” Immunoassays! Falsely Positive Anticytokine Antibody Tests Due to Reactivity with Bovine Serum Albumin in Rheumatoid Arthritis (The Swedish TIRA Project)

Objective.

To evaluate (1) to what extent sera from healthy subjects and patients with rheumatoid arthritis (RA) contain antibodies to bovine serum albumin (BSA); and (2) if anti-BSA antibodies interfere with results of enzyme-linked immunoassays (ELISA) containing BSA.

Methods.

The ELISA used was a previously developed in-house assay of autoantibodies to tumor necrosis factor (TNF). Anti-TNF and anti-BSA antibodies were analyzed by ELISA in 189 patients with early RA and 186 healthy blood donors. TNF preparations containing either BSA or human serum albumin (HSA) as carrier proteins were used as antigens in the anti-TNF assay. The presence and levels of antibodies were analyzed in relation to disease course and to the presence/absence of rheumatoid factor (RF).

Results.

In patients with RA, anti-TNF/BSA levels strongly correlated with anti-BSA levels (r = 0.81, p < 0.001), whereas anti-TNF/HSA did not (r = −0.09). Neither the presence nor the levels of anti-BSA in RA patients were associated with disease progression, and antibody levels were not significantly altered compared to controls (p = 0.11). IgG reactivity with TNF/HSA was neglible. In paired sera, preincubation with BSA abolished the anti-TNF/BSA reactivity. There were no indications of RF interference with anti-BSA or anti-TNF reactivity.

Conclusion.

Antibodies to BSA are common in patients with RA as well as in healthy individuals. Their presence does not seem to be associated with RA disease activity or disease course, but may severely interfere with ELISA containing BSA. The use of BSA as a “blocking agent” or carrier protein in immunoassays should therefore be avoided.

Serum levels of autoantibodies against C-reactive protein correlate with renal disease activity and response to therapy in lupus nephritis

Introduction

Serum levels of C-reactive protein (CRP) seldom reflect disease activity in systemic lupus erythematosus (SLE). We have previously shown that autoantibodies against neo-epitopes of CRP often occur in SLE, but that this does not explain the modest CRP response seen in flares. However, we have repeatedly found that anti-CRP levels parallel lupus disease activity, with highest levels in patients with renal involvement; thus, we aimed to study anti-CRP in a material of well-characterized lupus nephritis patients.

Methods

Thirty-eight patients with lupus nephritis were included. Treatment with corticosteroids combined with cyclophosphamide, mycophenolate mofetil or rituximab was started after baseline kidney biopsy. A second biopsy was taken after ≥ 6 months. Serum creatinine, cystatin C, complement, anti-dsDNA, anti-CRP and urinalysis were done on both occasions. Biopsies were evaluated regarding World Health Organisation (WHO) class and indices of activity and chronicity. Renal disease activity was estimated using the British Isles Lupus Assessment Group (BILAG) index.

Results

At baseline, 34/38 patients had renal BILAG-A; 4/38 had BILAG-B. Baseline biopsies showed WHO class III (n = 8), IV (n = 19), III to IV/V (n = 3) or V (n = 8) nephritis. Seventeen out of 38 patients were anti-CRP-positive at baseline, and six at follow-up. Overall, anti-CRP levels had dropped at follow-up (P < 0.0001) and anti-CRP levels correlated with renal BILAG (r = 0.29, P = 0.012). A positive anti-CRP test at baseline was superior to anti-dsDNA and C1q in predicting poor response to therapy as judged by renal BILAG. Baseline anti-CRP levels correlated with renal biopsy activity (r = 0.33, P = 0.045), but not with chronicity index. Anti-CRP levels were positively correlated with anti-dsDNA (fluorescence-enhanced immunoassay: r = 0.63, P = 0.0003; Crithidia luciliae immunofluorescence microscopy test: r = 0.44, P < 0.0001), and inversely with C3 (r = 0.35, P = 0.007) and C4 (r = 0.29, P = 0.02), but not with C1q (r = 0.14, P = 0.24). No associations with urinary components, creatinine, cystatin C or the glomerular filtration rate were found.

Conclusions

In the present study, we demonstrate a statistically significant correlation between anti-CRP levels and histopathological activity in lupus nephritis, whereas a baseline positive anti-CRP test predicted poor response to therapy. Our data also confirm previous findings of associations between anti-CRP and disease activity. This indicates that anti-CRP could be helpful to assess disease activity and response to therapy in SLE nephritis, and highlights the hypothesis of a pathogenetic role for anti-CRP antibodies in lupus nephritis.

An injectable nucleus replacement as an adjunct to microdiscectomy: 2 year follow-up in a pilot clinical study

Literature indicates that loss of disc tissue from herniation and/or surgery can accelerate degeneration of the disc. The associated loss of disc height may correspond with recurrent back and/or leg pain. A novel hydrogel has been developed to replace lost nucleus pulposus and potentially restore normal disc biomechanics following herniation and surgery. A single-center, non-randomized, prospective feasibility study was undertaken to investigate the use of NuCore Injectable Nucleus hydrogel (Spine Wave, Inc., Shelton, CT, USA) as a replacement for nuclear tissue lost to herniation and microdiscectomy. Fourteen patients were enrolled at the authors' hospital as the initial site in a worldwide multicenter pilot study. Subjects who were entered into the study suffered from radicular pain due to single-level herniated nucleus pulposus and were non-respondent to conservative therapy. Following a standard microdiscectomy procedure, the hydrogel material was injected into the nuclear void to replace what tissue had been lost to the herniation and surgery. Leg and back pain, function and disability scores were monitored pre- and post-operatively through 2 years. Neurologic and physical evaluations, blood and serum analyses, and radiographic evaluations of disc height and implant stability were also performed. Results showed significant improvement for leg and back pain, as well as function scores. No complications or device related adverse events were observed. MR controls confirmed stable position of the implants with no reherniations. Radiographic measurements indicated better maintenance of disc height compared to literature data on microdiscectomy alone. The NuCore material appears to protect the disc from early collapse following microdiscectomy; and therefore, may have the potential to slow the degenerative cascade of the spinal segment over time.