Combinatorial antibody library from multiple sclerosis patients reveals antibodies that cross-react with myelin basic protein and EBV antigen

Mimicking the brain: Epstein-Barr virus and foreign agents as drivers of neuroimmune attack in multiple sclerosis

T cells have an essential role in adaptive immunity against pathogens and cancer, but failure of thymic tolerance mechanisms can instead lead to escape of T cells with the ability to attack host tissues. Multiple sclerosis (MS) occurs when structures such as myelin and neurons in the central nervous system (CNS) are the target of autoreactive immune responses, resulting in lesions in the brain and spinal cord which cause varied and episodic neurological deficits. A role for autoreactive T cell and antibody responses in MS is likely, and mounting evidence implicates Epstein-Barr virus (EBV) in disease mechanisms. In this review we discuss antigen specificity of T cells involved in development and progression of MS. We examine the current evidence that these T cells can target multiple antigens such as those from pathogens including EBV and briefly describe other mechanisms through which viruses could affect disease. Unravelling the complexity of the autoantigen T cell repertoire is essential for understanding key events in the development and progression of MS, with wider implications for development of future therapies.

Surveying the Metabolic and Dysfunctional Profiles of T Cells and NK Cells in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Millions globally suffer from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The inflammatory symptoms, illness onset, recorded outbreak events, and physiological variations provide strong indications that ME/CFS, at least sometimes, has an infectious origin, possibly resulting in a chronic unidentified viral infection. Meanwhile, studies exposing generalized metabolic disruptions in ME/CFS have stimulated interest in isolated immune cells with an altered metabolic state. As the metabolism dictates the cellular function, dissecting the biomechanics of dysfunctional immune cells in ME/CFS can uncover states such as exhaustion, senescence, or anergy, providing insights into the consequences of these phenotypes in this disease. Despite the similarities that are seen metabolically between ME/CFS and other chronic viral infections that result in an exhausted immune cell state, immune cell exhaustion has not yet been verified in ME/CFS. This review explores the evidence for immunometabolic dysfunction in ME/CFS T cell and natural killer (NK) cell populations, comparing ME/CFS metabolic and functional features to dysfunctional immune cell states, and positing whether anergy, exhaustion, or senescence could be occurring in distinct immune cell populations in ME/CFS, which is consistent with the hypothesis that ME/CFS is a chronic viral disease. This comprehensive review of the ME/CFS immunometabolic literature identifies CD8+ T cell exhaustion as a probable contender, underscores the need for further investigation into the dysfunctional state of CD4+ T cells and NK cells, and explores the functional implications of molecular findings in these immune-cell types. Comprehending the cause and impact of ME/CFS immune cell dysfunction is critical to understanding the physiological mechanisms of ME/CFS, and developing effective treatments to alleviate the burden of this disabling condition.

Markers of Epstein-Barr Virus Infection in Patients with Multiple Sclerosis

Viral infections have been suspected of being involved in the pathogenesis of certain autoimmune diseases for many years. Epstein-Barr virus (EBV), a DNA virus belonging to the Herpesviridae family, is thought to be associated with the onset and/or the progression of multiple sclerosis (MS), systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome and type 1 diabetes. The lifecycle of EBV consists of lytic cycles and latency programmes (0, I, II and III) occurring in infected B-cells. During this lifecycle, viral proteins and miRNAs are produced. This review provides an overview of the detection of EBV infection, focusing on markers of latency and lytic phases in MS. In MS patients, the presence of latency proteins and antibodies has been associated with lesions and dysfunctions of the central nervous system (CNS). In addition, miRNAs, expressed during lytic and latency phases, may be detected in the CNS of MS patients. Lytic reactivations of EBV can occur in the CNS of patients as well, with the presence of lytic proteins and T-cells reacting to this protein in the CNS of MS patients. In conclusion, markers of EBV infection can be found in MS patients, which argues in favour of a relationship between EBV and MS.

The Role of Viral Infections in the Onset of Autoimmune Diseases

Autoimmune diseases (AIDs) are the consequence of a breach in immune tolerance, leading to the inability to sufficiently differentiate between self and non-self. Immune reactions that are targeted towards self-antigens can ultimately lead to the destruction of the host's cells and the development of autoimmune diseases. Although autoimmune disorders are comparatively rare, the worldwide incidence and prevalence is increasing, and they have major adverse implications for mortality and morbidity. Genetic and environmental factors are thought to be the major factors contributing to the development of autoimmunity. Viral infections are one of the environmental triggers that can lead to autoimmunity. Current research suggests that several mechanisms, such as molecular mimicry, epitope spreading, and bystander activation, can cause viral-induced autoimmunity. Here we describe the latest insights into the pathomechanisms of viral-induced autoimmune diseases and discuss recent findings on COVID-19 infections and the development of AIDs.

Myelin Basic Protein Fragmentation by Engineered Human Proteasomes with Different Catalytic Phenotypes Revealed Direct Peptide Ligands of MS-Associated and Protective HLA Class I Molecules

Proteasomes exist in mammalian cells in multiple combinatorial variants due to the diverse regulatory particles and exchange of catalytic subunits. Here, using biotin carboxyl carrier domain of transcarboxylase from Propionibacterium shermanii fused with different proteasome subunits of catalytic and regulatory particles, we report comprehensive characterization of highly homogenous one-step purified human constitutive and immune 20S and 26S/30S proteasomes. Hydrolysis of a multiple sclerosis (MS) autoantigen, myelin basic protein (MBP), by engineered human proteasomes with different catalytic phenotypes, revealed that peptides which may be directly loaded on the HLA class I molecules are produced mainly by immunoproteasomes. We detected at least five MBP immunodominant core regions, namely, LPRHRDTGIL, SLPQKSHGR, QDENPVVHFF, KGRGLSLSRF and GYGGRASDY. All peptides, except QDENPVVHFF, which originates from the encephalitogenic MBP part, were associated with HLA I alleles considered to increase MS risk. Prediction of the affinity of HLA class I to this peptide demonstrated that MS-protective HLA-A*44 and -B*35 molecules are high-affinity binders, whereas MS-associated HLA-A*23, -A*24, -A*26 and -B*51 molecules tend to have moderate to low affinity. The HLA-A*44 molecules may bind QDENPVVHFF and its deamidated form in several registers with unprecedently high affinity, probably linking its distinct protective phenotype with thymic depletion of the repertoire of autoreactive cytotoxic T cells or induction of CD8+ regulatory T cells, specific to the encephalitogenic MBP peptide.

MHC Class II Presentation in Autoimmunity

Antigen presentation by major histocompatibility complex class II (MHC-II) molecules is crucial for eliciting an efficient immune response by CD4+ T cells and maintaining self-antigen tolerance. Some MHC-II alleles are known to be positively or negatively associated with the risk of the development of different autoimmune diseases (ADs), including those characterized by the emergence of autoreactive T cells. Apparently, the MHC-II presentation of self-antigens contributes to the autoimmune T cell response, initiated through a breakdown of central tolerance to self-antigens in the thymus. The appearance of autoreactive T cell might be the result of (i) the unusual interaction between T cell receptors (TCRs) and self-antigens presented on MHC-II; (ii) the posttranslational modifications (PTMs) of self-antigens; (iii) direct loading of the self-antigen to classical MHC-II without additional nonclassical MHC assistance; (iv) the proinflammatory environment effect on MHC-II expression and antigen presentation; and (v) molecular mimicry between foreign and self-antigens. The peculiarities of the processes involved in the MHC-II-mediated presentation may have crucial importance in the elucidation of the mechanisms of triggering and developing ADs as well as for clarification on the protective effect of MHC-II alleles that are negatively associated with ADs.

Extracellular Vesicles in Chronic Demyelinating Diseases: Prospects in Treatment and Diagnosis of Autoimmune Neurological Disorders

Extracellular vesicles (EVs) represent membrane-enclosed structures that are likely to be secreted by all living cell types in the animal organism, including cells of peripheral (PNS) and central nervous systems (CNS). The ability to cross the blood-brain barrier (BBB) provides the possibility not only for various EV-loaded molecules to be delivered to the brain tissues but also for the CNS-to-periphery transmission of these molecules. Since neural EVs transfer proteins and RNAs are both responsible for functional intercellular communication and involved in the pathogenesis of neurodegenerative diseases, they represent attractive diagnostic and therapeutic targets. Here, we discuss EVs' role in maintaining the living organisms' function and describe deviations in EVs' structure and malfunctioning during various neurodegenerative diseases.

Multiple Sclerosis Is Associated with Immunoglobulin Germline Gene Variation of Transitional B Cells

The regulatory functions of the B-cell compartment play an important role in the development and suppression of the immune response. Disruption of their anti-inflammatory functions may lead to the acceleration of immunopathological processes, and to autoimmune diseases, in particular. Unfortunately, the exact mechanism underlying the functioning and development of regulatory B cells (Breg) has not yet been fully elucidated. Almost nothing is known about their specificity and the structure of their B-cell receptors (BCRs). In this research, we analyzed the BCR repertoire of the transitional Breg (tBreg) subpopulation with the CD19+CD24highCD38high phenotype in patients with multiple sclerosis (MS), using next-generation sequencing (NGS). We show, for the first time, that the immunoglobulin germline distribution in the tBreg subpopulation is different between MS patients and healthy donors. The registered variation was more significant in patients with a more severe form of the disease, highly active MS (HAMS), compared to those with benign MS (BMS). Our data suggest that during MS development, deviations in the immunoglobulin Breg repertoire occur already at the early stage of B-cell maturation, namely at the stage of tBregs: between immature B cells in the bone marrow and mature peripheral B cells.

Autoreactive lymphocytes in multiple sclerosis: Pathogenesis and treatment target

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by destruction of the myelin sheath structure. The loss of myelin leads to damage of a neuron’s axon and cell body, which is identified as brain lesions on magnetic resonance image (MRI). The pathogenesis of MS remains largely unknown. However, immune mechanisms, especially those linked to the aberrant lymphocyte activity, are mainly responsible for neuronal damage. Th1 and Th17 populations of lymphocytes were primarily associated with MS pathogenesis. These lymphocytes are essential for differentiation of encephalitogenic CD8⁺ T cell and Th17 lymphocyte crossing the blood brain barrier and targeting myelin sheath in the CNS. B-lymphocytes could also contribute to MS pathogenesis by producing anti-myelin basic protein antibodies. In later studies, aberrant function of Treg and Th9 cells was identified as contributing to MS. This review summarizes the aberrant function and count of lymphocyte, and the contributions of these cell to the mechanisms of MS. Additionally, we have outlined the novel MS therapeutics aimed to amend the aberrant function or counts of these lymphocytes.

Deconvolution of B cell receptor repertoire in multiple sclerosis patients revealed a delay in tBreg maturation

Background

B lymphocytes play a pivotal regulatory role in the development of the immune response. It was previously shown that deficiency in B regulatory cells (Bregs) or a decrease in their anti-inflammatory activity can lead to immunological dysfunctions. However, the exact mechanisms of Bregs development and functioning are only partially resolved. For instance, only a little is known about the structure of their B cell receptor (BCR) repertoires in autoimmune disorders, including multiple sclerosis (MS), a severe neuroinflammatory disease with a yet unknown etiology. Here, we elucidate specific properties of B regulatory cells in MS.

Methods

We performed a prospective study of the transitional Breg (tBreg) subpopulations with the CD19+CD24highCD38high phenotype from MS patients and healthy donors by (i) measuring their content during two diverging courses of relapsing-remitting MS: benign multiple sclerosis (BMS) and highly active multiple sclerosis (HAMS); (ii) analyzing BCR repertoires of circulating B cells by high-throughput sequencing; and (iii) measuring the percentage of CD27+ cells in tBregs.

Results

The tBregs from HAMS patients carry the heavy chain with a lower amount of hypermutations than tBregs from healthy donors. The percentage of transitional CD24highCD38high B cells is elevated, whereas the frequency of differentiated CD27+ cells in this transitional B cell subset was decreased in the MS patients as compared with healthy donors.

Conclusions

Impaired maturation of regulatory B cells is associated with MS progression.

Role of the gut microbiome in multiple sclerosis: From etiology to therapeutics

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS that affects around one million people in the United States. Predisposition or protection from this disease is linked with both genetic and environmental factors. In recent years, gut microbiome has emerged as an important environmental factor in the pathobiology of MS. The gut microbiome supports various physiologic functions, including the development and maintenance of the host immune system, the perturbation of which is known as dysbiosis and has been linked with multiple diseases including MS. We and others have shown that people with MS (PwMS) have gut dysbiosis that is characterized by specific gut bacteria being enriched or depleted. Consequently, there is an emphasis on determining the mechanism(s) through which gut bacteria and/or their metabolites alter the course of MS through their ability to provide protection, predispose individuals, or promote disease progression. Improving our understanding of these mechanisms will allow us to harness the enormous potential of the gut microbiome as a diagnostic and/or therapeutic agent. In this chapter, we will discuss current advances in microbiome research in the context of MS, including a review of specific bacteria that are currently linked with this disease, potential mechanisms of disease pathogenesis, and the utility of microbiome-based therapy for PwMS.

Multiple sclerosis and myelin basic protein: insights into protein disorder and disease

Myelin basic protein (MBP) is an abundant protein in central nervous system (CNS) myelin. MBP has long been studied as a factor in the pathogenesis of the autoimmune neurodegenerative disease multiple sclerosis (MS). MS is characterized by CNS inflammation, demyelination, and axonal loss. One of the main theories on the pathogenesis of MS suggests that exposure to foreign antigens causes the activation of cross-reactive T cells in genetically susceptible individuals, with MBP being a possible autoantigen. While a direct role for MBP as a primary antigen in human MS is unclear, it is clear that MBP and its functions in myelin formation and long-term maintenance are linked to MS. This review looks at some key molecular characteristics of MBP and its relevance to MS, as well as the mechanisms of possible molecular mimicry between MBP and some viral antigens. We also discuss the use of serum anti-myelin antibodies as biomarkers for disease. MBP is a prime example of an apparently simple, but in fact biochemically and structurally complex molecule, which is closely linked to both normal nervous system development and neurodegenerative disease.

The Emerging World of Microbiome in Autoimmune Disorders: Opportunities and Challenges

Trillions of commensal bacteria colonizing humans (microbiome) have emerged as essential player(s) in human health. The alteration of the same has been linked with diseases including autoimmune disorders such as multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis. Gut bacteria are separated from the host through a physical barrier such as skin or gut epithelial lining. However, the perturbation in the healthy bacterial community (gut dysbiosis) can compromise gut barrier integrity, resulting in translocation of bacterial contents across the epithelial barrier (leaky gut). Bacterial contents such as lipopolysaccharide and bacterial antigens can induce a systemic inflammatory environment through activation and induction of immune cells. The biggest question in the field is whether inflammation causes gut dysbiosis or dysbiosis leads to disease induction or propagation, i.e., it is inside out or outside in or both. In this review, we first discuss the microbiome profiling studies in various autoimmune disorders, followed by a discussion of potential mechanisms through which microbiome is involved in the pathobiology of diseases. A better understanding of the role of the microbiome in health and disease will help us harness the power of commensal bacteria for the development of novel therapeutic agents to treat autoimmune disorders.

Molecular Interventions towards Multiple Sclerosis Treatment

Multiple sclerosis (MS) is an autoimmune life-threatening disease, afflicting millions of people worldwide. Although the disease is non-curable, considerable therapeutic advances have been achieved through molecular immunotherapeutic approaches, such as peptides vaccination, administration of monoclonal antibodies, and immunogenic copolymers. The main aims of these therapeutic strategies are to shift the MS-related autoimmune response towards a non-inflammatory T helper 2 (Th2) cells response, inactivate or ameliorate cytotoxic autoreactive T cells, induce secretion of anti-inflammatory cytokines, and inhibit recruitment of autoreactive lymphocytes to the central nervous system (CNS). These approaches can efficiently treat autoimmune encephalomyelitis (EAE), an essential system to study MS in animals, but they can only partially inhibit disease progress in humans. Nevertheless, modern immunotherapeutic techniques remain the most promising tools for the development of safe MS treatments, specifically targeting the cellular factors that trigger the initiation of the disease.

Probing Surface Membrane Receptors Using Engineered Bacteriophage Bioconjugates

Specific recognition of ligands by surface receptors of eukaryotic cells is a fundamental process in sensing of the exogenous environment, including cell-to-cell communication. These interactions are therefore widely probed in both basic studies and drug development to enhance or interrupt them. Here, we designed a high-throughput publicly available platform for visualization and selection of eukaryotic cells according to the specificity of surface-exposed receptors by consolidation of phage display and flow cytometry techniques. Polypeptide ligands for membrane receptors are incorporated into every copy of p3 protein of M13K07 bacteriophage, which is intracellularly biotinylated to further accept PE-Cy7-labled streptavidin. Transgenic antigen-specific B-cells expressing membrane-tethered lymphoid B-cell receptor in a single-chain format interacted with engineered bacteriophages exposing the polypeptide ligand with an unprecedented selectivity of 97% and a false-positive detection value of 2.0%. Multivalent binding of the phage bioconjugates with the receptor provided significantly better specificity and sensitivity allowing application of engineered bacteriophage bioconjugates at a concentration 3 orders of magnitude lower in comparison with synthetic biotinylated peptide. We suggest that the platform described in this work may be applied either for routine staining or characterization of orphan membrane receptors exposed on the surface of living mammalian cells in their native environment.

Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disorder. Although all MS patients initially show a relapsing-remitting course, 20-50% subsequently enter a chronic progressive course at 10-20 years after onset that greatly influences their activities of daily living. There are 2.5 million MS patients worldwide with large regional and racial differences. In particular, there are many MS patients among Caucasians living in Europe, while the disease is relatively rare in Asians and Africans.Although MS is regarded as an autoimmune disease, many factors such as genetic background, environmental factors, and sex are involved in its pathogenesis. While the immunological mechanisms remain to be fully elucidated, invasion of autoreactive T cells into the central nervous system (CNS) tissue is considered the first step of the disease. These T cells react with myelin antigens and initiate demyelination of the CNS by activating cytotoxic T cells, macrophages, and B cells through the release of inflammatory cytokines. As a treatment option, disease-modifying therapies have recently been developed to prevent the recurrence of MS in addition to conventional treatment with corticosteroids for acute relapse. However, there are still few effective treatments for the chronic progressive phase, and it is thus imperative to decipher the mechanism for chronic progression.

Multiple Sclerosis Re-Examined: Essential and Emerging Clinical Concepts

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system characterized by exacerbations of neurological dysfunction due to inflammatory demyelination. Neurologic symptoms typically present in young adulthood and vary based on the site of inflammation, although weakness, sensory impairment, brainstem dysfunction, and vision loss are common. MS occurs more frequently in women and its development is complex-genetics, hormones, geography, vitamin D, and viral exposure all play roles. Early MS is characterized by relapsing-remitting course and inflammation of the white matter, although as patients age, the disease often transitions to a pathologically distinct secondary progressive phase with gradual disability accrual affecting gait, coordination, and bladder function. A minority of patients (10%) have disease that is progressive at onset. In the past decade, there has been a remarkable expansion in disease-modifying therapy for MS, but treatment of progressive disease remains a challenge. This article reviews foundational concepts in MS and emerging work that has reshaped understanding of the disease, providing new insight for therapeutic advance.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome - Evidence for an autoimmune disease

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a frequent and severe chronic disease drastically impairing life quality. The underlying pathomechanism is incompletely understood yet but there is convincing evidence that in at least a subset of patients ME/CFS has an autoimmune etiology. In this review, we will discuss current autoimmune aspects for ME/CFS. Immune dysregulation in ME/CFS has been frequently described including changes in cytokine profiles and immunoglobulin levels, T- and B-cell phenotype and a decrease of natural killer cell cytotoxicity. Moreover, autoantibodies against various antigens including neurotransmitter receptors have been recently identified in ME/CFS individuals by several groups. Consistently, clinical trials from Norway have shown that B-cell depletion with rituximab results in clinical benefits in about half of ME/CFS patients. Furthermore, recent studies have provided evidence for severe metabolic disturbances presumably mediated by serum autoantibodies in ME/CFS. Therefore, further efforts are required to delineate the role of autoantibodies in the onset and pathomechanisms of ME/CFS in order to better understand and properly treat this disease.

Analysis of Immunogenicity of Intracellular CTAR Fragments of Epstein-Barr Virus Latent Phase Protein LMP1

Intracellular fragments of latent phase protein LMP1 of Epstein-Barr virus, denoted as CTAR1/2/3, can trigger a variety of cell cascades and contribute to the transforming potential of the virus. Generation of recombinant proteins CTAR1/2/3 is expected to yield more ample data on functional and immunogenic characteristics of LMP1. We created genetic constructs for prokaryotic expression of LMP1 CTAR fragments and selected optimal conditions for their production and purification. Using a new library of LMP1 CTAR fragments, we carried out epitope mapping of a diagnostic anti-LMP1 antibody S12. Analysis of polyclonal serum antibodies from mice immunized with full-length LMP1 confirmed immunogenicity of CTAR elements comparable with that of full-length protein.

Pulverization characteristics of coal affected by magmatic intrusion and analysis of the abnormal gas desorption index on drill cuttings

The gas desorption index of drill cuttings is a basic index that measures the initial desorption capacities of coal seams and predicts coal seam gas outbursts. Following a long period of gas drainage in the No.7 coal seam of the No.86 mining area in the Haizi coal mine, the gas desorption index of drill cuttings was still found to be much higher than the threshold value for outburst risks. This abnormal phenomenon led to the present study of the rational selection of test methods and objects in this context. In this study, particle size distribution, pore structure and gas desorption characteristics of coal samples in anomalous areas were analyzed. We found that desorption characteristics are related to particle size and particle size varies in relation to tectonic stress and magmatic intrusions. It appears that the anomalous readings are related to particle size of the coal, resulting from tectonic/magmatic pulverization. Furthermore, measured particle size of drill cuttings is not actually reflective of coal particle size – larger particles may be comprised of multiple smaller particles. The results show that coal samples with particle size <1 mm accounts for 76.3% of total samples and coal samples with particle size >1 mm only accounts for 23.7% of total samples. The porosity and total pore volume increase as the particle size decreases. The specific surface area increases with decreasing pore diameter. Transitional pores and micropores increase the specific surface area of the coal sample considerably. The desorption capacity increases with decreasing particle size. The additional tectonic stress caused by magmatic intrusion has a crushing effect, and 1–3 mm particles used in test were composed of a large amount of smaller particles, eventually resulting in abnormal gas desorption index phenomena. Therefore, we proposed an improved method for measuring the gas desorption index of pulverized coal.

Genetic Engineering of Native Chain Combinations of B-Cell Repertoires on the Surface of Methylotrophic Yeasts Pichia pastoris

We designed genetic constructs for exposing Fab-fragment library of natively paired single cell B-cell receptors on the surface of Pichia pastoris yeast cells. We have previously obtained the A17 antibody in our laboratory [6]. In this study we showed that the newly designed genetic constructs provide a compatible level of A17 antibody Fab fragment on the surface of yeast cells as well as in the case of vectors containing DNA fragments corresponding to each chain of the antibody. The data suggest that the developed approach for constructing immunoglobulin gene libraries is adequate and fully convenient for studying properties of the real human B-lymphocyte repertoire.

Exposure to the Epstein-Barr Viral Antigen Latent Membrane Protein 1 Induces Myelin-Reactive Antibodies In Vivo

Multiple sclerosis (MS) is an autoimmune chronic inflammatory disease of the central nervous system (CNS). Cross-reactivity of neuronal proteins with exogenous antigens is considered one of the possible mechanisms of MS triggering. Previously, we showed that monoclonal myelin basic protein (MBP)-specific antibodies from MS patients cross-react with Epstein–Barr virus (EBV) latent membrane protein 1 (LMP1). In this study, we report that exposure of mice to LMP1 results in induction of myelin-reactive autoantibodies in vivo. We posit that chronic exposure or multiple acute exposures to viral antigen may redirect B cells from production of antiviral antibodies to antibodies, specific to myelin antigen. However, even in inbred animals, which are almost identical in terms of their genomes, such an effect is only observed in 20–50% of animals, indicating that this change occurs by chance, rather than systematically. Cross-immunoprecipitation analysis showed that only part of anti-MBP antibodies from LMP1-immunized mice might simultaneously bind LMP1. In contrast, the majority of anti-LMP1 antibodies from MBP-immunized mice bind MBP. De novo sequencing of anti-LMP1 and anti-MBP antibodies by mass spectrometry demonstrated enhanced clonal diversity in LMP1-immunized mice in comparison with MBP-immunized mice. We suggest that induction of MBP-reactive antibodies in LMP1-immunized mice may be caused by either Follicular dendritic cells (FDCs) or by T cells that are primed by myelin antigens directly in CNS. Our findings help to elucidate the still enigmatic link between EBV infection and MS development, suggesting that myelin-reactive antibodies raised as a response toward EBV protein LMP1 are not truly cross-reactive but are primarily caused by epitope spreading.

Serological profiling of the EBV immune response in Chronic Fatigue Syndrome using a peptide microarray

BACKGROUND

Epstein-Barr-Virus (EBV) plays an important role as trigger or cofactor for various autoimmune diseases. In a subset of patients with Chronic Fatigue Syndrome (CFS) disease starts with infectious mononucleosis as late primary EBV-infection, whereby altered levels of EBV-specific antibodies can be observed in another subset of patients.

METHODS

We performed a comprehensive mapping of the IgG response against EBV comparing 50 healthy controls with 92 CFS patients using a microarray platform. Patients with multiple sclerosis (MS), systemic lupus erythematosus (SLE) and cancer-related fatigue served as controls. 3054 overlapping peptides were synthesised as 15-mers from 14 different EBV proteins. Array data was validated by ELISA for selected peptides. Prevalence of EBV serotypes was determined by qPCR from throat washing samples.

RESULTS

EBV type 1 infections were found in patients and controls. EBV seroarray profiles between healthy controls and CFS were less divergent than that observed for MS or SLE. We found significantly enhanced IgG responses to several EBNA-6 peptides containing a repeat sequence in CFS patients compared to controls. EBNA-6 peptide IgG responses correlated well with EBNA-6 protein responses. The EBNA-6 repeat region showed sequence homologies to various human proteins.

CONCLUSION

Patients with CFS had a quite similar EBV IgG antibody response pattern as healthy controls. Enhanced IgG reactivity against an EBNA-6 repeat sequence and against EBNA-6 protein is found in CFS patients. Homologous sequences of various human proteins with this EBNA-6 repeat sequence might be potential targets for antigenic mimicry.

Viruses and Multiple Sclerosis: From Mechanisms and Pathways to Translational Research Opportunities

Viruses are directly or indirectly implicated in multiple sclerosis (MS). Here, we review the evidence on the virus-related pathophysiology of MS, introduce common experimental models, and explore the ways in which viruses cause demyelination. By emphasizing knowledge gaps, we highlight future research directions for effective MS diagnostics and therapies: (i) identifying biomarkers for at-risk individuals, (ii) searching for direct evidence of specific causative viruses, (iii) establishing the contribution of host genetic factors and viruses, and (iv) investigating the contribution of immune regulation at extra-CNS sites. Research in these areas is likely to be facilitated by the application of high-throughput technologies, the development of systems-based bioinformatic approaches, careful selection of experimental models, and the acquisition of high-quality clinical material for tissue-based research.

Multitarget selection of catalytic antibodies with β-lactamase activity using phage display

β-lactamase enzymes responsible for bacterial resistance to antibiotics are among the most important health threats to the human population today. Understanding the increasingly vast structural motifs responsible for the catalytic mechanism of β-lactamases will help improve the future design of new generation antibiotics and mechanism-based inhibitors of these enzymes. Here we report the construction of a large murine single chain fragment variable (scFv) phage display library of size 2.7 × 10⁹ with extended diversity by combining different mouse models. We have used two molecularly different inhibitors of the R-TEM β-lactamase as targets for selection of catalytic antibodies with β-lactamase activity. This novel methodology has led to the isolation of five antibody fragments, which are all capable of hydrolyzing the β-lactam ring. Structural modeling of the selected scFv has revealed the presence of different motifs in each of the antibody fragments potentially responsible for their catalytic activity. Our results confirm (a) the validity of using our two target inhibitors for the in vitro selection of catalytic antibodies endowed with β-lactamase activity, and (b) the plasticity of the β-lactamase active site responsible for the wide resistance of these enzymes to clinically available inhibitors and antibiotics.

The A Allele of the Single-Nucleotide Polymorphism rs630923 Creates a Binding Site for MEF2C Resulting in Reduced CXCR5 Promoter Activity in B-Cell Lymphoblastic Cell Lines

Chemokine receptor CXCR5 is highly expressed in B-cells and under normal conditions is involved in their migration to specific areas of secondary lymphoid organs. B-cells are known to play an important role in various autoimmune diseases including multiple sclerosis (MS) where areas of demyelinating lesions attract B-cells by overexpressing CXCL13, the CXCR5 ligand. In this study, we aimed to determine the functional significance of single-nucleotide polymorphism rs630923 (A/C), which is located in cxcr5 gene promoter, and its common allele is associated with increased risk of MS. Using bioinformatics and pull-down assay in B-lymphoblastic cell lines, we showed that protective minor rs630923 "A" allele created functional binding site for MEF2C transcription factor. Elevated MEF2C expression in B-cells correlated with reduced activity of cxcr5 promoter containing rs630923 "A" allele. This effect that was fully neutralized by MEF2C-directed siRNA may mechanistically explain the protective role of the rs630923 minor allele in MS. Using site-directed mutagenesis of the cxcr5 gene promoter, we were unable to find any experimental evidence for the previously proposed role of NFκB transcription factors in rs630923-mediated CXCR5 promoter regulation. Thus, our results identify MEF2C as a possible mediator of protective function of the rs630923 "A" allele in MS.

The Pathogenesis of the Demyelinating Form of Guillain-Barre Syndrome (GBS): Proteo-peptidomic and Immunological Profiling of Physiological Fluids

Acute inflammatory demyelinating polyneuropathy (AIDP) - the main form of Guillain-Barre syndrome-is a rare and severe disorder of the peripheral nervous system with an unknown etiology. One of the hallmarks of the AIDP pathogenesis is a significantly elevated cerebrospinal fluid (CSF) protein level. In this paper CSF peptidome and proteome in AIDP were analyzed and compared with multiple sclerosis and control patients. A total protein concentration increase was shown to be because of even changes in all proteins rather than some specific response, supporting the hypothesis of protein leakage from blood through the blood-nerve barrier. The elevated CSF protein level in AIDP was complemented by activization of protein degradation and much higher peptidome diversity. Because of the studies of the acute motor axonal form, Guillain-Barre syndrome as a whole is thought to be associated with autoimmune response against neurospecific molecules. Thus, in AIDP, autoantibodies against cell adhesion proteins localized at Ranvier's nodes were suggested as possible targets in AIDP. Indeed, AIDP CSF peptidome analysis revealed cell adhesion proteins degradation, however no reliable dependence on the corresponding autoantibodies levels was found. Proteome analysis revealed overrepresentation of Gene Ontology groups related to responses to bacteria and virus infections, which were earlier suggested as possible AIDP triggers. Immunoglobulin blood serum analysis against most common neuronal viruses did not reveal any specific pathogen; however, AIDP patients were more immunopositive in average and often had polyinfections. Cytokine analysis of both AIDP CSF and blood did not show a systemic adaptive immune response or general inflammation, whereas innate immunity cytokines were up-regulated. To supplement the widely-accepted though still unproven autoimmunity-based AIDP mechanism we propose a hypothesis of the primary peripheral nervous system damaging initiated as an innate immunity-associated local inflammation following neurotropic viruses egress, whereas the autoantibody production might be an optional complementary secondary process.

Use of the VH6-1 gene segment to code for anti-interleukin-18 autoantibodies in multiple sclerosis

We investigated whether levels and repertoires of anti-interleukin-18 (IL-18) autoantibodies (auto-Abs) differ in multiple sclerosis (MS) patients and healthy donors (HDs). IL-18 concentration in MS patients' sera was higher than in HD, but the level of anti-IL-18 auto-Abs was lower in MS patients. Correlation patterns of IL-18/anti-IL-18 auto-Abs system differed in HD and MS patients, so we have compared segment composition of the anti-IL-18 single-chain variable fragments (scFvs) selected from MS and naïve phage display libraries. Considerable differences between anti-IL-18 auto-Abs of these libraries were found. MS panel contained auto-Abs displaying both signs of "fetal" and somatically hypermutated repertoires. Naïve panel mainly contained the naïve antibodies. These variations from the norm are possible results of abnormal regulation of the repertoire perhaps determined by remodeling of the molecular mechanisms involved in the V(D)J recombination and/or abnormal selection by antigen in MS pathogenesis.

Environmental Factors and Their Regulation of Immunity in Multiple Sclerosis

In multiple sclerosis (MS), environmental factors and genetic traits cooperate in the induction of the chronic activation of immune cells to produce the brain pathology. Epidemiology has focused on different environmental risk factors but certainly virus infection, smoking, vitamin D levels, and sunlight exposure are the most relevant. What is certainly less clear is the way in which these external factors are able to induce and sustain the internal pathology process of the disease. Epigenetics has been recently focused on trying to shed light on this aspect. As a matter of fact epigenetic changes are highly sensitive to environmental factors that therefore may influence the susceptibility to the disease by acting through epigenetic modifications. In this chapter we discuss the most relevant environmental factors and how they may affect the immune response in MS. Finally, we discuss the possible role of the microbiota in inducing autoimmunity in MS.

Virus-Induced Demyelination: The Case for Virus(es) in Multiple Sclerosis

Multiple Sclerosis (MS) is the most common demyelinating disease of man with over 400,000 cases in the United States and over 2.5 million cases worldwide. There are over 64,000 citations in Pubmed dating back as far as 1887. Much has been learned over the past 129 years with a recent burst in therapeutic options (mostly anti-inflammatory) with newer medications in development that are neuroprotective and/or neuroreparative. However, with all these advancements the cause of MS remains elusive. There is a clear interplay of genetic, immunologic, and environmental factors that influences both the development and progression of this disorder. This chapter will give a brief overview of the history and pathogenesis of MS with attention to how host immune responses in genetically susceptible individuals contribute to the MS disease process. In addition, we will explore the role of infectious agents in MS as potential “triggers” of disease. Models of virus-induced demyelination will be discussed, with an emphasis on the recent interest in human herpesviruses and the role they may play in MS disease pathogenesis. Although we remain circumspect as to the role of any microbial pathogen in MS, we suggest that only through well-controlled serological, cellular immune, molecular, and animal studies we will be able to identify candidate agents. Ultimately, clinical interventional trials that either target a specific pathogen or class of pathogens will be required to make definitive links between the suspected agent and MS.

Neuroproteomic profiling of human body fluids

Analysis of protein expression and abundance provides a possibility to extend the current knowledge on disease-associated processes and pathways. The human brain is a complex organ and dysfunction or damage can give rise to a variety of neurological diseases. Although many proteins potentially reflecting disease progress are originating from brain, the scarce availability of human tissue material has lead to utilization of body fluids such as cerebrospinal fluid and blood in disease-related research. Within the most common neurological disorders, much effort has been spent on studying the role of a few hallmark proteins in disease pathogenesis but despite extensive investigation, the signatures they provide seem insufficient to fully understand and predict disease progress. In order to expand the view the field of neuroproteomics has lately emerged alongside developing technologies, such as affinity proteomics and mass spectrometry, for multiplexed and high-throughput protein profiling. Here, we provide an overview of how such technologies have been applied to study neurological disease and we also discuss some important considerations concerning discovery of disease-associated profiles.

Clinical and experimental studies of multiple sclerosis in Russia: experience of the leading national research centers

Mechanisms of axonal damage and adaptive capacity in multiple sclerosis (MS), including cortical reorganization, have been actively studied in recent years. The lack of regenerative capabilities and the irreversibility of neurodegeneration in MS are critical factors for the optimization of MS treatment. In this study, we present the results of clinical and basic studies in the field of MS by two leading Russian centers. Clinical and neuroimaging correlations show that spinal damage in MS is accompanied by functional reorganization of the cerebral cortex, which is determined not only by the efferent component but also by the afferent component. Comparative analysis of MS treatment with both interferon β1b (IFN-β1b) and IFN-β1a at a dosage of 22 µg for 3 years through subcutaneous administration and glatiramer acetate showed equally high efficiency in reducing the number of exacerbations in relapsing-remitting MS and secondary-progressive MS. We demonstrate a reduced risk of disability in relapsing-remitting MS and secondary-progressive MS patients in all groups treated with IFN-β1 and glatiramer acetate. MS appears to be a disease that would greatly benefit from the development of personalized therapy; thus, adequate molecular predictors of myelin degradation are greatly needed. Therefore, novel ideas related to the viral hypothesis of the etiology of MS and new targets for therapeutic intervention are currently being developed. In this manuscript, we discuss findings of both clinical practice and fundamental research reflecting challenges and future directions of MS treatment in the Russian Federation.

The beneficial effects of vitamin D3 on reducing antibody titers against Epstein-Barr virus in multiple sclerosis patients

Recently, the relationship between immunoreactivity to Epstein-Barr virus (EBV) and hypo-vitamin D in multiple sclerosis (MS) patients has been described. The aim of this study was to investigate whether vitamin D3 supplementation in MS patients could influence the immune response against latent EBV infection. Forty MS patients were recruited in this study. Twenty-seven patients were supplemented with 50,000 IU/week of vitamin D3 for 6 months and thirteen enrolled as controls. 25-Hydroxyvitamin D (25OHD) levels and IgG titers against EBNA1 and VCA were determined pre- and post-supplementation. All the patients were seropositive for EBV prior to vitamin D supplementation. In this cohort, 22.5% and 47.5% of the MS patients had deficient and insufficient levels of 25OHD, respectively. Our findings confirm that antibody titers against EBV in MS patients rise after the onset of the disease and indicate that vitamin D3 supplementation could limit augmentation of these titers in MS patients.

Molecular Mimicry and Autoimmunity

The term Molecular mimicry describes the sequence similarity between foreign (microorganism's peptides) and self peptides (the host's antigen). This phenomenon has been recently discovered as a one of the major mechanism in which there is a break-down of self-tolerance of the immune system following autoimmunity. After a short preface, the chapter contains examples of common infectious agents and their role in autoimmune diseases. Later on, it describes the autoimmune diseases in which there was found a relation to infectious agents via molecular mimicry mechanism. The data is summarized in two tables.

Generation of “LYmph Node Derived Antibody Libraries” (LYNDAL) for selecting fully human antibody fragments with therapeutic potential

The development of efficient strategies for generating fully human monoclonal antibodies with unique functional properties that are exploitable for tailored therapeutic interventions remains a major challenge in the antibody technology field. Here, we present a methodology for recovering such antibodies from antigen-encountered human B cell repertoires. As the source for variable antibody genes, we cloned immunoglobulin G (IgG)-derived B cell repertoires from lymph nodes of 20 individuals undergoing surgery for head and neck cancer. Sequence analysis of unselected “LYmph Node Derived Antibody Libraries” (LYNDAL) revealed a naturally occurring distribution pattern of rearranged antibody sequences, representing all known variable gene families and most functional germline sequences. To demonstrate the feasibility for selecting antibodies with therapeutic potential from these repertoires, seven LYNDAL from donors with high serum titers against herpes simplex virus (HSV) were panned on recombinant glycoprotein B of HSV-1. Screening for specific binders delivered 34 single-chain variable fragments (scFvs) with unique sequences. Sequence analysis revealed extensive somatic hypermutation of enriched clones as a result of affinity maturation. Binding of scFvs to common glycoprotein B variants from HSV-1 and HSV-2 strains was highly specific, and the majority of analyzed antibody fragments bound to the target antigen with nanomolar affinity. From eight scFvs with HSV-neutralizing capacity in vitro,the most potent antibody neutralized 50% HSV-2 at 4.5 nM as a dimeric (scFv)2. We anticipate our approach to be useful for recovering fully human antibodies with therapeutic potential.

The role of phage display in therapeutic antibody discovery

Phage display involves the expression of selected proteins on the surface of filamentous phage through fusion with phage coat protein, with the genetic sequence packaged within, linking phenotype to genotype selection. When combined with antibody libraries, phage display allows for rapid in vitro selection of antigen-specific antibodies and recovery of their corresponding coding sequence. Large non-immune and synthetic human libraries have been constructed as well as smaller immune libraries based on capturing a single individual’s immune repertoire. This completely in vitro process allows for isolation of antibodies against poorly immunogenic targets as well as those that cannot be obtained by animal immunization, thus further expanding the utility of the approach. Phage antibody display represents the first developed methodology for high throughput screening for human therapeutic antibody candidates. Recently, other methods have been developed for generation of fully human therapeutic antibodies, such as single B-cell screening, next-generation genome sequencing and transgenic mice with human germline B-cell genes. While each of these have their particular advantages, phage display has remained a key methodology for human antibody discovery due its in vitro process. Here, we review the continuing role of this technique alongside other developing technologies for therapeutic antibody discovery.

Novel somatic single nucleotide variants within the RNA binding protein hnRNP A1 in multiple sclerosis patients

Some somatic single nucleotide variants (SNVs) are thought to be pathogenic, leading to neurological disease. We hypothesized that heterogeneous nuclear ribonuclear protein A1 (hnRNP A1), an autoantigen associated with multiple sclerosis (MS) would contain SNVs. MS patients develop antibodies to hnRNP A1 (293-304), an epitope within the M9 domain (AA (268-305)) of hnRNP A1. M9 is hnRNP A1's nucleocytoplasmic transport domain, which binds transportin-1 (TPNO-1) and allows for hnRNP A1's transport into and out of the nucleus. Genomic DNA sequencing of M9 revealed nine novel SNVs that resulted in an amino acid substitution in MS patients that were not present in controls. SNVs occurred within the TPNO-1 binding domain (hnRNP A1 (268-289)) and the MS IgG epitope (hnRNP A1 (293-304)), within M9.  In contrast to the nuclear localization of wild type (WT) hnRNP A1, mutant hnRNP A1 mis-localized to the cytoplasm, co-localized with stress granules and caused cellular apoptosis. Whilst WT hnRNP A1 bound TPNO-1, mutant hnRNP A1 showed reduced TPNO-1 binding. These data suggest SNVs in hnRNP A1 might contribute to pathogenesis of MS.

Novel somatic single nucleotide variants within the RNA binding protein hnRNP A1 in multiple sclerosis patients

Some somatic single nucleotide variants (SNVs) are thought to be pathogenic, leading to neurological disease. We hypothesized that heterogeneous nuclear ribonuclear protein A1 (hnRNP A1), an autoantigen associated with multiple sclerosis (MS) would contain SNVs. MS patients develop antibodies to hnRNP A1 (293-304), an epitope within the M9 domain (AA (268-305)) of hnRNP A1. M9 is hnRNP A1's nucleocytoplasmic transport domain, which binds transportin-1 (TPNO-1) and allows for hnRNP A1's transport into and out of the nucleus. Genomic DNA sequencing of M9 revealed nine novel SNVs that resulted in an amino acid substitution in MS patients that were not present in controls. SNVs occurred within the TPNO-1 binding domain (hnRNP A1 (268-289)) and the MS IgG epitope (hnRNP A1 (293-304)), within M9.  In contrast to the nuclear localization of wild type (WT) hnRNP A1, mutant hnRNP A1 mis-localized to the cytoplasm, co-localized with stress granules and caused cellular apoptosis. Whilst WT hnRNP A1 bound TPNO-1, mutant hnRNP A1 showed reduced TPNO-1 binding. These data suggest SNVs in hnRNP A1 might contribute to pathogenesis of MS.

Exploitation of rolling circle amplification for the construction of large phage-display antibody libraries

Phage display antibody libraries have proven to have a significant role in the discovery of therapeutic antibodies and polypeptides with desired biological and physicochemical properties. Obtaining a large and diverse phage display antibody library, however, is always a challenging task. Various steps of this technique can still undergo optimization in order to obtain an efficient library. In the construction of a single chain fragment variable (scFv) phage display library, the cloning of the scFv fragments into a phagemid vector is of crucial importance. An efficient restriction enzyme digestion of the scFv DNA leads to its proper ligation with the phagemid followed by its successful cloning and expression. Here, we are reporting a different approach to enhance the efficiency of the restriction enzyme digestion step. We have exploited rolling circle amplification (RCA) to produce a long strand of DNA with tandem repeats of scFv sequences, which is found to be highly susceptible to restriction digestion. With this important modification, we are able to construct a large phage display antibody library of naive SJL/J mice. The size of the library is estimated as ~10(8) clones. The number of clones containing a scFv fragment is estimated at 90%. Hence, the present results could considerably aid the utilization of the phage-display technique in order to get an efficiently large antibody library.

Role of κ→λ light-chain constant-domain switch in the structure and functionality of A17 reactibody

The engineering of catalytic function in antibodies requires precise information on their structure. Here, results are presented that show how the antibody domain structure affects its functionality. The previously designed organophosphate-metabolizing reactibody A17 has been re-engineered by replacing its constant κ light chain by the λ chain (A17λ), and the X-ray structure of A17λ has been determined at 1.95 Å resolution. It was found that compared with A17κ the active centre of A17λ is displaced, stabilized and made more rigid owing to interdomain interactions involving the CDR loops from the VL and VH domains. These VL/VH domains also have lower mobility, as deduced from the atomic displacement parameters of the crystal structure. The antibody elbow angle is decreased to 126° compared with 138° in A17κ. These structural differences account for the subtle changes in catalytic efficiency and thermodynamic parameters determined with two organophosphate ligands, as well as in the affinity for peptide substrates selected from a combinatorial cyclic peptide library, between the A17κ and A17λ variants. The data presented will be of interest and relevance to researchers dealing with the design of antibodies with tailor-made functions.

Heavy-light chain interrelations of MS-associated immunoglobulins probed by deep sequencing and rational variation

The mechanisms triggering most of autoimmune diseases are still obscure. Autoreactive B cells play a crucial role in the development of such pathologies and, in particular, production of autoantibodies of different specificities. The combination of deep-sequencing technology with functional studies of antibodies selected from highly representative immunoglobulin combinatorial libraries may provide unique information on specific features in the repertoires of autoreactive B cells. Here, we have analyzed cross-combinations of the variable regions of human immunoglobulins against the myelin basic protein (MBP) previously selected from a multiple sclerosis (MS)-related scFv phage-display library. On the other hand, we have performed deep sequencing of the sublibraries of scFvs against MBP, Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1), and myelin oligodendrocyte glycoprotein (MOG). Bioinformatics analysis of sequencing data and surface plasmon resonance (SPR) studies have shown that it is the variable fragments of antibody heavy chains that mainly determine both the affinity of antibodies to the parent autoantigen and their cross-reactivity. It is suggested that LMP1-cross-reactive anti-myelin autoantibodies contain heavy chains encoded by certain germline gene segments, which may be a hallmark of the EBV-specific B cell subpopulation involved in MS triggering.

Deficient EBV-specific B- and T-cell response in patients with chronic fatigue syndrome

Epstein-Barr virus (EBV) has long been discussed as a possible cause or trigger of Chronic Fatigue Syndrome (CFS). In a subset of patients the disease starts with infectious mononucleosis and both enhanced and diminished EBV-specific antibody titers have been reported. In this study, we comprehensively analyzed the EBV-specific memory B- and T-cell response in patients with CFS. While we observed no difference in viral capsid antigen (VCA)-IgG antibodies, EBV nuclear antigen (EBNA)-IgG titers were low or absent in 10% of CFS patients. Remarkably, when analyzing the EBV-specific memory B-cell reservoir in vitro a diminished or absent number of EBNA-1- and VCA-antibody secreting cells was found in up to 76% of patients. Moreover, the ex vivo EBV-induced secretion of TNF-α and IFN-γ was significantly lower in patients. Multicolor flow cytometry revealed that the frequencies of EBNA-1-specific triple TNF-α/IFN-γ/IL-2 producing CD4(+) and CD8(+) T-cell subsets were significantly diminished whereas no difference could be detected for HCMV-specific T-cell responses. When comparing EBV load in blood immune cells, we found more frequently EBER-DNA but not BZLF-1 RNA in CFS patients compared to healthy controls suggesting more frequent latent replication. Taken together, our findings give evidence for a deficient EBV-specific B- and T-cell memory response in CFS patients and suggest an impaired ability to control early steps of EBV reactivation. In addition the diminished EBV response might be suitable to develop diagnostic marker in CFS.

Antimyelin antibodies as predictors of disability after clinically isolated syndrome

There is controversy whether determination of antibodies against myelin, myelin oligodendrocyte glycoprotein, and myelin basic protein in serum from patients with a first episode suggestive of multiple sclerosis is of prognostic value. We evaluated whether detection of antimyelin antibodies in serum indicates a worse course with earlier time to a second relapse and increased progression of disability. We conducted a prospective study at the Department of Neurology, Inselspital Bern, Switzerland from 2004 to 2008 in patients presenting with a clinically isolated syndrome (CIS) and a follow-up of at least 4 months. Antimyelin antibodies were assessed by Western blot. Results were correlated with clinical course and sex. Among 93 consecutive patients with a CIS, 74 (80%) were positive for either one or both antimyelin antibodies. A relapse occurred in 49 (53%) and the median EDSS was 2 (range 1-3.5) after a mean observation period of 20 months. Presence of antimyelin antibodies at CIS neither increased the risk for a second relapse nor for progression of disability. Stratification for gender did not reveal differences for any of the clinical surrogates. The sole determination of antimyelin antibodies in serum is of limited prognostic value for the identification of patients with different short-term course.

Protein array-based profiling of CSF identifies RBPJ as an autoantigen in multiple sclerosis

OBJECTIVE

To profile the reactivity of CSF-derived immunoglobulin from patients with multiple sclerosis (MS) against a large panel of antigens, to identify disease-specific reactivities.

METHODS

CSF from subjects with MS with elevated immunoglobulin G and CSF from control subjects presenting with other inflammatory neurologic disease were screened against a protein array consisting of 9,393 proteins. Reactivity to a candidate protein identified using these arrays was confirmed with ELISA and immunocytochemistry.

RESULTS

Autoantibodies against one protein on the array, recombination signal binding protein for immunoglobulin kappa J region (RBPJ), discriminated between patients with MS and controls (p = 0.0052). Using a large validation cohort, we found a higher prevalence of autoantibodies against RBPJ in the CSF of patients with MS (12.5%) compared with the CSF of patients with other neurologic diseases (1.6%; p = 0.02) by ELISA. This difference in reactivity was restricted to the CSF as serum reactivity against RBPJ did not differ between patients and controls. The presence of CSF autoantibodies against RBPJ was further confirmed by immunocytochemistry.

CONCLUSIONS

These data indicate that RBPJ, a ubiquitous protein of the Notch signaling pathway that plays an important role in Epstein-Barr virus infection, is a novel MS autoantigen candidate that is recognized by CSF-derived immunoglobulin G in a subset of patients with MS.

Heterogeneous catalysis on the phage surface: Display of active human enteropeptidase

Enteropeptidase (EC 3.4.21.9) plays a key role in mammalian digestion as the enzyme that physiologically activates trypsinogen by highly specific cleavage of the trypsinogen activation peptide following the recognition sequence D4K. The high specificity of enteropeptidase makes it a powerful tool in modern biotechnology. Here we describe the application of phage display technology to express active human enteropeptidase catalytic subunits (L-HEP) on M13 filamentous bacteriophage. The L-HEP/C122S gene was cloned in the g3p-based phagemid vector pHEN2m upstream of the sequence encoding the phage g3p protein and downstream of the signal peptide-encoding sequence. Heterogeneous catalysis of the synthetic peptide substrate (GDDDDK-β-naphthylamide) cleavage by phage-bound L-HEP was shown to have kinetic parameters similar to those of soluble enzyme, with the respective Km values of 19 μM and 20 μM and kcat of 115 and 92 s(-1). Fusion proteins containing a D4K cleavage site were cleaved with phage-bound L-HEP/C122S as well as by soluble L-HEP/C122S, and proteolysis was inhibited by soybean trypsin inhibitor. Rapid large-scale phage production, one-step purification of phage-bound L-HEP, and easy removal of enzyme activity from reaction samples by PEG precipitation make our approach suitable for the efficient removal of various tag sequences fused to the target proteins. The functional phage display technology developed in this study can be instrumental in constructing libraries of mutants to analyze the effect of structural changes on the activity and specificity of the enzyme or generate its desired variants for biotechnological applications.