Humoral-targeted immunotherapies in multiple sclerosis

Recombinant Antibody Fragments for Neurological Disorders: An Update

Recombinant antibody fragments are promising alternatives to full-length immunoglobulins, creating big opportunities for the pharmaceutical industry. Nowadays, antibody fragments such as antigen-binding fragments (Fab), single-chain fragment variable (scFv), single-domain antibodies (sdAbs), and bispecific antibodies (bsAbs) are being evaluated as diagnostics or therapeutics in preclinical models and in clinical trials. Immunotherapy approaches, including passive transfer of protective antibodies, have shown therapeutic efficacy in several animal models of Alzheimer's disease (AD), Parkinson's disease (PD), frontotemporal dementia (FTD), Huntington's disease (HD), transmissible spongiform encephalopathies (TSEs) and multiple sclerosis (MS). There are various antibodies approved by the Food and Drug Administration (FDA) for treating multiple sclerosis and two amyloid beta-specific humanized antibodies, Aducanumab and Lecanemab, for AD. Our previous review summarized data on recombinant antibodies evaluated in pre-clinical models for immunotherapy of neurodegenerative diseases. Here, we explore recent studies in this fascinating research field, give an update on new preventive and therapeutic applications of recombinant antibody fragments for neurological disorders and discuss the potential of antibody fragments for developing novel approaches for crossing the blood-brain barrier (BBB) and targeting cells and molecules of interest in the brain.

A Comprehensive Review on Neuroimmunology: Insights from Multiple Sclerosis to Future Therapeutic Developments

This review delves into neuroimmunology, focusing on its relevance to multiple sclerosis (MS) and potential treatment advancements. Neuroimmunology explores the intricate relationship between the immune system and the central nervous system (CNS). Understanding these mechanisms is vital for grasping the pathophysiology of diseases like MS and for devising innovative treatments. This review introduces foundational neuroimmunology concepts, emphasizing the role of immune cells, cytokines, and blood-brain barrier in CNS stability. It highlights how their dysregulation can contribute to MS and discusses genetic and environmental factors influencing MS susceptibility. Cutting-edge research methods, from omics techniques to advanced imaging, have revolutionized our understanding of MS, offering valuable diagnostic and prognostic tools. This review also touches on the intriguing gut-brain axis, examining how gut microbiota impacts neuroimmunological processes and its potential therapeutic implications. Current MS treatments, from immunomodulatory drugs to disease-modifying therapies, are discussed alongside promising experimental approaches. The potential of personalized medicine, cell-based treatments, and gene therapy in MS management is also explored. In conclusion, this review underscores neuroimmunology's significance in MS research, suggesting that a deeper understanding could pave the way for more tailored and effective treatments for MS and similar conditions. Continued research and collaboration in neuroimmunology are essential for enhancing patient outcomes.

Safety and efficacy of COVID-19 vaccines in multiple sclerosis patients

COVID-19 vaccination is recommended for multiple sclerosis patients. Disease-modifying therapies can influence the safety and efficacy of COVID-19 vaccines. RNA, DNA, protein, and inactivated vaccines are likely safe for multiple sclerosis patients. A few incidences of central demyelination were reported with viral vector vaccines, but their benefits likely outweigh their risks if alternatives are unavailable. Live-attenuated vaccines should be avoided whenever possible in treated patients. Interferon-beta, glatiramer acetate, teriflunomide, fumarates, and natalizumab are not expected to impact vaccine efficacy, while cell-depleting agents (ocrelizumab, rituximab, ofatumumab, alemtuzumab, and cladribine) and sphingosine-1-phosphate modulators will likely attenuate vaccine responses. Coordinating vaccine timing with dosing regimens for some therapies may optimize vaccine efficacy.

Evaluation of safety of rituximab in patients with multiple sclerosis: A retrograde study

Background: The study aimed to judge the safety and possible side effects of rituximab (RTX) drug in patients with multiple sclerosis (MS). Methods: This retrospective observational study was performed on 91 patients with MS who had been treated with RTX between 2016 and 2019. Each patient was visited and examined a minimum of once. The side effects of the drug and therefore the drug-related reactions to the injection were asked via phone calls, which were recorded separately as mild, moderate, and severe modes with the necessity for hospitalization. Results: A total of 91 patients were enrolled within the study: 80 patients with relapsing-remitting MS (RRMS), 6 patients with secondary progressive MS (SPMS), and 5 patients with primary progressive MS (PPMS). The mean age of the patients was 32.18 ± 8.71 years (18 to 60 years). The injection-related side effects occurred in 30.8% of the injections, most of which were mild and one of the mild complications was urinary tract infection (UTI). Two cases of complications with moderate severity were recorded. Conclusion: The observations from this study demonstrated that RTX did not cause serious complications in patients with MS.

Recombinant Antibody Fragments for Neurodegenerative Diseases

BACKGROUND

Recombinant antibody fragments are promising alternatives to full-length immunoglobulins and offer important advantages compared with conventional monoclonal antibodies: extreme specificity, higher affinity, superior stability and solubility, reduced immunogenicity as well as easy and inexpensive large-scale production.

OBJECTIVE

In this article we will review and discuss recombinant antibodies that are being evaluated for neurodegenerative diseases in pre-clinical models and in clinical studies and will summarize new strategies that are being developed to optimize their stability, specificity and potency for advancing their use.

METHODS

Articles describing recombinant antibody fragments used for neurological diseases were selected (PubMed) and evaluated for their significance.

RESULTS

Different antibody formats such as single-chain fragment variable (scFv), single-domain antibody fragments (VHHs or sdAbs), bispecific antibodies (bsAbs), intrabodies and nanobodies, are currently being studied in pre-clinical models of cancer as well as infectious and autoimmune diseases and many of them are being tested as therapeutics in clinical trials. Immunotherapy approaches have shown therapeutic efficacy in several animal models of Alzheimer´s disease (AD), Parkinson disease (PD), dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), Huntington disease (HD), transmissible spongiform encephalopathies (TSEs) and multiple sclerosis (MS). It has been demonstrated that recombinant antibody fragments may neutralize toxic extra- and intracellular misfolded proteins involved in the pathogenesis of AD, PD, DLB, FTD, HD or TSEs and may target toxic immune cells participating in the pathogenesis of MS.

CONCLUSION

Recombinant antibody fragments represent a promising tool for the development of antibody-based immunotherapeutics for neurodegenerative diseases.

Human Tregs Made Antigen Specific by Gene Modification: The Power to Treat Autoimmunity and Antidrug Antibodies with Precision

Human regulatory CD4⁺ T cells (Tregs) are potent immunosuppressive lymphocytes responsible for immune tolerance and homeostasis. Since the seminal reports identifying Tregs, vast research has been channeled into understanding their genesis, signature molecular markers, mechanisms of suppression, and role in disease. This research has opened the doors for Tregs as a potential therapeutic for diseases and disorders such as multiple sclerosis, type I diabetes, transplantation, and immune responses to protein therapeutics, like factor VIII. Seminal clinical trials have used polyclonal Tregs, but the frequency of antigen-specific Tregs among polyclonal populations is low, and polyclonal Tregs may risk non-specific immunosuppression. Antigen-specific Treg therapy, which uses genetically modified Tregs expressing receptors specific for target antigens, greatly mitigates this risk. Building on the principles of T-cell receptor cloning, chimeric antigen receptors (CARs), and a novel CAR derivative, called B-cell antibody receptors, our lab has developed different types of antigen-specific Tregs. This review discusses the current research and optimization of gene-modified antigen-specific human Tregs in our lab in several disease models. The preparations and considerations for clinical use of such Tregs also are discussed.

Disease-modifying therapy for multiple sclerosis

ABSTRACT 

Remarkable expansion of new diagnostic criteria and disease-modifying treatments for multiple sclerosis has occurred in the last two decades. Revision of diagnostic criteria and characterization of disease course has allowed earlier diagnosis and better characterization of individual patients. With the current treatment armamentarium in the USA offering 11 agents, patients can now benefit from increasingly individualized therapy. The therapeutic decision-making process has become more complex, with the availability of multiple medications. Relative efficacy, potentially severe adverse events, tolerability issues and patient's preferences must now all be considered so that increasingly disease management more frequently involves physicians with multiple sclerosis subspecialty expertise. This article aims to provide a clinically oriented and concise review of currently available, as well as emerging, disease-modifying treatment therapies in multiple sclerosis.

Multiple sclerosis-a quiet revolution

Multiple sclerosis (MS) has been thought to be a complex and indecipherable disease, and poorly understood with regards to aetiology. Here, we suggest an emphatically positive view of progress over several decades in the understanding and treatment of MS, particularly focusing on advances made within the past 20 years. As with virtually all complex disorders, MS is caused by the interaction of genetic and environmental factors. In recent years, formidable biochemical, bioinformatic, epidemiological and neuroimaging tools have been brought to bear on research into the causes of MS. While susceptibility to the disease is now relatively well accounted for, disease course is not and remains a salient challenge. In the therapeutic realm, numerous agents have become available, reflecting the fact that the disease can be attacked successfully at many levels and using varied strategies. Tailoring therapies to individuals, risk mitigation and selection of first-line as compared with second-line medications remain to be completed. In our view, the MS landscape has been comprehensively and irreversibly transformed by this progress. Here we focus on MS therapeutics-the most meaningful outcome of research efforts.

Gene therapy delivery of myelin oligodendrocyte glycoprotein (MOG) via hematopoietic stem cell transfer induces MOG-specific B cell deletion

The various mechanisms that have been described for immune tolerance govern our ability to control self-reactivity and minimize autoimmunity. However, the capacity to genetically manipulate the immune system provides a powerful avenue to supplement this natural tolerance in an Ag-specific manner. We have previously shown in the mouse model of experimental autoimmune encephalomyelitis that transfer of bone marrow (BM) transduced with retrovirus encoding myelin oligodendrocyte glycoprotein (MOG) promotes disease resistance and CD4(+) T cell deletion within the thymus. However, the consequence of this strategy on B cell tolerance is not known. Using BM from IgH(MOG) mice that develop MOG-specific B cell receptors, we generated mixed chimeras together with BM-encoding MOG. In these animals, the development of MOG-specific B cells was abrogated, resulting in a lack of MOG-specific B cells in all B cell compartments examined. This finding adds a further dimension to our understanding of the mechanisms of tolerance that are associated with this gene therapy approach to treating autoimmunity and may have important implications for Ab-mediated autoimmune disorders.

Current understanding on the role of standard and immunoproteasomes in inflammatory/immunological pathways of multiple sclerosis

The ubiquitin-proteasome system is the major intracellular molecular machinery for protein degradation and maintenance of protein homeostasis in most human cells. As ubiquitin-proteasome system plays a critical role in the regulation of the immune system, it might also influence the development and progression of multiple sclerosis (MS). Both ex vivo analyses and animal models suggest that activity and composition of ubiquitin-proteasome system are altered in MS. Proteasome isoforms endowed of immunosubunits may affect the functionality of different cell types such as CD8⁺ and CD4⁺ T cells and B cells as well as neurons during MS development. Furthermore, the study of proteasome-related biomarkers, such as proteasome antibodies and circulating proteasomes, may represent a field of interest in MS. Proteasome inhibitors are already used as treatment for cancer and the recent development of inhibitors selective for immunoproteasome subunits may soon represent novel therapeutic approaches to the different forms of MS. In this review we describe the current knowledge on the potential role of proteasomes in MS and discuss the pro et contra of possible therapies for MS targeting proteasome isoforms.

Rituximab

Rituximab (Rituxan^®, MabThera^®, and Genentech/Roche) is a chimeric murine/human monoclonal IgG1k antibody directed against the CD20 antigen located at the surface of normal and malignant B lymphocytes.

Risk-benefit considerations in the treatment of relapsing-remitting multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system and mainly affects young adults. Its natural history has changed in recent years with the advent of disease-modifying drugs, which have been available since the early 1990s. The increasing number of first-line and second-line treatment options, together with the variable course of the disease and patient lifestyles and expectations, makes the therapeutic decision a real challenge. The aim of this review is to give a comprehensive overview of the main present and some future drugs for relapsing-remitting MS, including risk-benefit considerations, to enable readers to draw their own conclusions regarding the risk-benefit assessment of personalized treatment strategies, taking into account not only treatment-related but also disease-related risks. We performed a Medline literature search to identify studies on the treatment of MS with risk stratification and risk-benefit considerations. We focused our attention on studies of disease-modifying, immunomodulating, and immunosuppressive drugs, including monoclonal antibodies. Here we offer personal considerations, stemming from long-term experience in the treatment of MS and thorough discussions with other neurologists closely involved in the care of patients with the disease. MS specialists need to know not only the specific risks and benefits of single drugs, but also about drug interactions, either in simultaneous or serial combination therapy, and patient comorbidities, preferences, and fears. This has to be put into perspective, considering also the risks of untreated disease in patients with different clinical and radiological characteristics. There is no single best treatment strategy, but therapy has to be tailored to the patient. This is a time-consuming task, rich in complexity, and influenced by the attitude towards risk on the parts of both the patient and the clinical team. The broader the MS drug market becomes, the harder it will be for the clinician to help the patient decide which therapeutic strategy to opt for.