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International Journal of Molecular... Mar 2023NANOBODY® (a registered trademark of Ablynx N.V) molecules (Nbs), also referred to as single domain-based VHHs, are antibody fragments derived from heavy-chain only IgG... (Review)
Review
NANOBODY® (a registered trademark of Ablynx N.V) molecules (Nbs), also referred to as single domain-based VHHs, are antibody fragments derived from heavy-chain only IgG antibodies found in the family. Due to their small size, simple structure, high antigen binding affinity, and remarkable stability in extreme conditions, nanobodies possess the potential to overcome several of the limitations of conventional monoclonal antibodies. For many years, nanobodies have been of great interest in a wide variety of research fields, particularly in the diagnosis and treatment of diseases. This culminated in the approval of the world's first nanobody based drug (Caplacizumab) in 2018 with others following soon thereafter. This review will provide an overview, with examples, of (i) the structure and advantages of nanobodies compared to conventional monoclonal antibodies, (ii) methods used to generate and produce antigen-specific nanobodies, (iii) applications for diagnostics, and (iv) ongoing clinical trials for nanobody therapeutics as well as promising candidates for clinical development.
Topics: Single-Domain Antibodies; Antibodies, Monoclonal; Phagocytosis; Immunoglobulin G
PubMed: 36983063
DOI: 10.3390/ijms24065994 -
MAbs 2023Single-chain fragment variable (scFv) domains play an important role in antibody-based therapeutic modalities, such as bispecifics, multispecifics and chimeric antigen...
Single-chain fragment variable (scFv) domains play an important role in antibody-based therapeutic modalities, such as bispecifics, multispecifics and chimeric antigen receptor T cells or natural killer cells. However, scFv domains exhibit lower stability and increased risk of aggregation due to transient dissociation ("breathing") and inter-molecular reassociation of the two domains (VL and VH). We designed a novel strategy, referred to as stapling, that introduces two disulfide bonds between the scFv linker and the two variable domains to minimize scFv breathing. We named the resulting molecules stapled scFv (spFv). Stapling increased thermal stability (Tm) by an average of 10°C. In multiple scFv/spFv multispecifics, the spFv molecules display significantly improved stability, minimal aggregation and superior product quality. These spFv multispecifics retain binding affinity and functionality. Our stapling design was compatible with all antibody variable regions we evaluated and may be widely applicable to stabilize scFv molecules for designing biotherapeutics with superior biophysical properties.
Topics: Immunoglobulin Variable Region; Antibodies; Immunoglobulin Fragments
PubMed: 37074212
DOI: 10.1080/19420862.2023.2195517 -
Frontiers in Immunology 2022Antibodies play a critical role in linking the adaptive immune response to the innate immune system. In humans, antibodies are categorized into five classes, IgG, IgM,... (Review)
Review
Antibodies play a critical role in linking the adaptive immune response to the innate immune system. In humans, antibodies are categorized into five classes, IgG, IgM, IgA, IgE, and IgD, based on constant region sequence, structure, and tropism. In serum, IgG is the most abundant antibody, comprising 75% of antibodies in circulation, followed by IgA at 15%, IgM at 10%, and IgD and IgE are the least abundant. All human antibody classes are post-translationally modified by sugars. The resulting glycans take on many divergent structures and can be attached in an N-linked or O-linked manner, and are distinct by antibody class, and by position on each antibody. Many of these glycan structures on antibodies are capped by sialic acid. It is well established that the composition of the N-linked glycans on IgG exert a profound influence on its effector functions. However, recent studies have described the influence of glycans, particularly sialic acid for other antibody classes. Here, we discuss the role of glycosylation, with a focus on terminal sialylation, in the biology and function across all antibody classes. Sialylation has been shown to influence not only IgG, but IgE, IgM, and IgA biology, making it an important and unappreciated regulator of antibody function.
Topics: Humans; Immunoglobulin A; Immunoglobulin D; Immunoglobulin E; Immunoglobulin G; Immunoglobulin M; N-Acetylneuraminic Acid; Polysaccharides
PubMed: 35464485
DOI: 10.3389/fimmu.2022.818736 -
Science Translational Medicine Oct 2022The mucosal origins hypothesis of rheumatoid arthritis (RA) proposes a central role for mucosal immune responses in the initiation or perpetuation of the systemic...
The mucosal origins hypothesis of rheumatoid arthritis (RA) proposes a central role for mucosal immune responses in the initiation or perpetuation of the systemic autoimmunity that occurs with disease. However, the connection between the mucosa and systemic autoimmunity in RA remains unclear. Using dual immunoglobulin A (IgA) and IgG family plasmablast-derived monoclonal autoantibodies obtained from peripheral blood of individuals at risk for RA, we identified cross-reactivity between RA-relevant autoantigens and bacterial taxa in the closely related families and . After generating bacterial isolates within the genus from the feces of an individual, we confirmed monoclonal antibody binding and CD4 T cell activation in individuals with RA compared to control individuals. In addition, when isolate 7 but not isolate 1 colonized germ-free mice, it stimulated T17 cell expansion, serum RA-relevant IgG autoantibodies, and joint swelling reminiscent of early RA, with histopathology characterized by antibody deposition and complement activation. Systemic immune responses were likely due to mucosal invasion along with the generation of colon-isolated lymphoid follicles driving increased fecal and serum IgA by isolate 7, because B and CD4 T cell depletion not only halted intestinal immune responses but also eliminated detectable clinical disease. In aggregate, these findings demonstrate a mechanism of RA pathogenesis through which a specific intestinal strain of bacteria can drive systemic autoantibody generation and joint-centered antibody deposition and immune activation.
Topics: Mice; Animals; Immunoglobulin A; Autoantibodies; Arthritis, Rheumatoid; Autoantigens; Immunoglobulin G; Antibodies, Monoclonal
PubMed: 36288282
DOI: 10.1126/scitranslmed.abn5166 -
Cell Reports Dec 2022Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages have escaped most receptor-binding domain (RBD)-targeting therapeutic neutralizing...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages have escaped most receptor-binding domain (RBD)-targeting therapeutic neutralizing antibodies (NAbs), which proves that previous NAb drug screening strategies are deficient against the fast-evolving SARS-CoV-2. Better broad NAb drug candidate selection methods are needed. Here, we describe a rational approach for identifying RBD-targeting broad SARS-CoV-2 NAb cocktails. Based on high-throughput epitope determination, we propose that broad NAb drugs should target non-immunodominant RBD epitopes to avoid herd-immunity-directed escape mutations. Also, their interacting antigen residues should focus on sarbecovirus conserved sites and associate with critical viral functions, making the antibody-escaping mutations less likely to appear. Following these criteria, a featured non-competing antibody cocktail, SA55+SA58, is identified from a large collection of broad sarbecovirus NAbs isolated from SARS-CoV-2-vaccinated SARS convalescents. SA55+SA58 potently neutralizes ACE2-utilizing sarbecoviruses, including circulating Omicron variants, and could serve as broad SARS-CoV-2 prophylactics to offer long-term protection, especially for individuals who are immunocompromised or with high-risk comorbidities.
Topics: Humans; Severe acute respiratory syndrome-related coronavirus; SARS-CoV-2; Broadly Neutralizing Antibodies; Combined Antibody Therapeutics; COVID-19; Antibodies, Neutralizing; Epitopes; Antibodies, Viral
PubMed: 36493787
DOI: 10.1016/j.celrep.2022.111845 -
Frontiers in Immunology 2022Cellular death, aging, and tissue damage trigger inflammation that leads to enzymatic and non-enzymatic lipid peroxidation of polyunsaturated fatty acids present on... (Review)
Review
Cellular death, aging, and tissue damage trigger inflammation that leads to enzymatic and non-enzymatic lipid peroxidation of polyunsaturated fatty acids present on cellular membranes and lipoproteins. This results in the generation of highly reactive degradation products, such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), that covalently modify free amino groups of proteins and lipids in their vicinity. These newly generated neoepitopes represent a unique set of damage-associated molecular patterns (DAMPs) associated with oxidative stress termed oxidation-specific epitopes (OSEs). OSEs are enriched on oxidized lipoproteins, microvesicles, and dying cells, and can trigger sterile inflammation. Therefore, prompt recognition and removal of OSEs is required to maintain the homeostatic balance. This is partially achieved by various humoral components of the innate immune system, such as natural IgM antibodies, pentraxins and complement components that not only bind OSEs but in some cases modulate their pro-inflammatory potential. Natural IgM antibodies are potent complement activators, and 30% of them recognize OSEs such as oxidized phosphocholine (OxPC-), 4-HNE-, and MDA-epitopes. Furthermore, OxPC-epitopes can bind the complement-activating pentraxin C-reactive protein, while MDA-epitopes are bound by C1q, C3a, complement factor H (CFH), and complement factor H-related proteins 1, 3, 5 (FHR-1, FHR-3, FHR-5). In addition, CFH and FHR-3 are recruited to 2-(ω-carboxyethyl)pyrrole (CEP), and full-length CFH also possesses the ability to attenuate 4-HNE-induced oxidative stress. Consequently, alterations in the innate humoral defense against OSEs predispose to the development of diseases associated with oxidative stress, as shown for the prototypical OSE, MDA-epitopes. In this mini-review, we focus on the mechanisms of the accumulation of OSEs, the pathophysiological consequences, and the interactions between different OSEs and complement components. Additionally, we will discuss the clinical potential of genetic variants in OSE-recognizing complement proteins - the OSE complotype - in the risk estimation of diseases associated with oxidative stress.
Topics: C-Reactive Protein; Complement C1q; Complement Factor H; Epitopes; Humans; Immunoglobulin M; Immunologic Factors; Inflammation; Lipids; Malondialdehyde; Phosphorylcholine
PubMed: 36248824
DOI: 10.3389/fimmu.2022.1010893 -
Cell Reports May 2022Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-neutralizing monoclonal antibodies (mAbs) can reduce the risk of hospitalization from coronavirus disease...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-neutralizing monoclonal antibodies (mAbs) can reduce the risk of hospitalization from coronavirus disease 2019 (COVID-19) when administered early. However, SARS-CoV-2 variants of concern (VOCs) have negatively affected therapeutic use of some authorized mAbs. Using a high-throughput B cell screening pipeline, we isolated LY-CoV1404 (bebtelovimab), a highly potent SARS-CoV-2 spike glycoprotein receptor binding domain (RBD)-specific antibody. LY-CoV1404 potently neutralizes authentic SARS-CoV-2, B.1.1.7, B.1.351, and B.1.617.2. In pseudovirus neutralization studies, LY-CoV1404 potently neutralizes variants, including B.1.1.7, B.1.351, B.1.617.2, B.1.427/B.1.429, P.1, B.1.526, B.1.1.529, and the BA.2 subvariant. Structural analysis reveals that the contact residues of the LY-CoV1404 epitope are highly conserved, except for N439 and N501. The binding and neutralizing activity of LY-CoV1404 is unaffected by the most common mutations at these positions (N439K and N501Y). The broad and potent neutralization activity and the relatively conserved epitope suggest that LY-CoV1404 has the potential to be an effective therapeutic agent to treat all known variants.
Topics: Antibodies, Monoclonal; Antibodies, Neutralizing; Antibodies, Viral; Epitopes; Humans; SARS-CoV-2; COVID-19 Drug Treatment
PubMed: 35568025
DOI: 10.1016/j.celrep.2022.110812 -
Journal of Innate Immunity 2009
Topics: Animals; Cellular Structures; DNA; Extracellular Space; Humans; Immunoproteins; Mice; Neutrophil Activation; Neutrophils
PubMed: 20375574
DOI: 10.1159/000207015 -
Clinics in Laboratory Medicine Mar 2022Severe acute respiratory syndrome coronavirus 2 (COVID)-19 has emerged as the greatest global health threat in generations. An unprecedented mobilization of researchers... (Review)
Review
Severe acute respiratory syndrome coronavirus 2 (COVID)-19 has emerged as the greatest global health threat in generations. An unprecedented mobilization of researchers has generated a wealth of data on humoral responses to SARS-CoV-2 within a year of the pandemic's beginning. The rapidly developed understanding of acute-phase antibody induction and medium-term antibody durability in COVID-19 is important at an individual level to inform patient care and a population level to help predict transmission dynamics. In this brief review, we will describe the development and maintenance of antibody responses to immunization and infections generally and the specific antibody dynamics observed for COVID-19. These crucial features of the humoral response have implications for the use of antibody therapeutics against the virus and can inform the likelihood of reinfection of individuals by the virus.
Topics: Antibodies, Viral; COVID-19; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; SARS-CoV-2
PubMed: 35153050
DOI: 10.1016/j.cll.2021.10.004 -
Frontiers in Immunology 2023Of the four human immunoglobulin G (IgG) subclasses, IgG4 is considered the least inflammatory, in part because it poorly activates the complement system. Regardless, in...
Of the four human immunoglobulin G (IgG) subclasses, IgG4 is considered the least inflammatory, in part because it poorly activates the complement system. Regardless, in IgG4 related disease (IgG4-RD) and in autoimmune disorders with high levels of IgG4 autoantibodies, the presence of these antibodies has been linked to consumption and deposition of complement components. This apparent paradox suggests that conditions may exist, potentially reminiscent of deposits, that allow for complement activation by IgG4. Furthermore, it is currently unclear how variable glycosylation and Fab arm exchange may influence the ability of IgG4 to activate complement. Here, we used well-defined, glyco-engineered monoclonal preparations of IgG4 and determined their ability to activate complement in a controlled system. We show that IgG4 can activate complement only at high antigen and antibody concentrations, the classical pathway. Moreover, elevated or reduced Fc galactosylation enhanced or diminished complement activation, respectively, with no apparent contribution from the lectin pathway. Fab glycans slightly reduced complement activation. Lastly, we show that bispecific, monovalent IgG4 resulting from Fab arm exchange is a less potent activator of complement than monospecific IgG4. Taken together, these results imply that involvement of IgG4-mediated complement activation in pathology is possible but unlikely.
Topics: Humans; Immunoglobulin G; Complement Activation; Autoimmune Diseases; Complement System Proteins; Autoantibodies
PubMed: 36776883
DOI: 10.3389/fimmu.2023.1087532