| 1. |
- Almazan, Nerea Martin, et al.
(author)
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Influenza-A mediated pre-existing immunity levels to SARS-CoV-2 could predict early COVID-19 outbreak dynamics
- 2023
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In: iScience. - : CELL PRESS. - 2589-0042. ; 26:12
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Journal article (peer-reviewed)abstract
- Susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is highly variable and could be mediated by a cross-protective pre-immunity. We identified 14 cross-reactive peptides between SARS-CoV-2 and influenza A H1N1, H3N2, and human herpesvirus (HHV)-6A/B with potential relevance. The H1N1 peptide NGVEGF was identical to a peptide in the most critical receptor binding motif in SARS-CoV-2 spike protein that interacts with the angiotensin converting enzyme 2 receptor. About 62%-73% of COVID-19-negative blood donors in Stockholm had antibodies to this peptide in the early pre-vaccination phase of the pandemic. Seasonal flu vaccination enhanced neutralizing capacity to SARS-CoV-2 and T cell immunity to this peptide. Mathematical modeling taking the estimated pre -immunity levels to flu into account could fully predict pre-Omicron SARS-CoV-2 outbreaks in Stockholm and India. This cross-immunity provides mechanistic explanations to the epidemiological observation that influenza vaccination protected people against early SARS-CoV-2 infections and implies that flu-mediated cross-protective immunity significantly dampened the first SARS-CoV-2 outbreaks.
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| 2. |
- Gkanatsiou, Eleni, et al.
(author)
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Characterization of monomeric and soluble aggregated A beta in Down's syndrome and Alzheimer's disease brains
- 2021
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In: Neuroscience Letters. - : Elsevier. - 0304-3940 .- 1872-7972. ; 754
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Journal article (peer-reviewed)abstract
- The major characteristics of Alzheimer's disease (AD) are amyloid plaques, consisting of aggregated beta amyloid (A beta) peptides, together with tau pathology (tangles, neuropil treads and dystrophic neurites surrounding the plaques), in the brain. Down's syndrome (DS) individuals are at increased risk to develop AD-type pathology; most DS individuals have developed substantial pathology already at the age of 40. DS individuals have an extra copy of chromosome 21, harbouring the amyloid precursor protein gene (APP). Our aim was to investigate the A beta peptide pattern in DS and AD brains to investigate differences in their amyloid deposition and aggregation, respectively. Cortical tissue from patients with DS (with amyloid pathology), sporadic AD and controls were homogenized and fractionated into TBS (water soluble) and formic acid (water insoluble) fractions. Immunoprecipitation (IP) was performed using a variety of antibodies targeting different A beta species including oligomeric A beta. Mass spectrometry was then used to evaluate the presence of A beta species in the different patient groups. A large number of A beta peptides were identified including A beta 1-X, 2-X, 3-X, 4-X, 5-X, 11-X, and A beta peptides extended N terminally of the BACE1 cleavage site and ending at amino 15 in the A beta sequence APP/A beta(-X to 15), as well as peptides post-translationally modified by pyroglutamate formation. Most A beta peptides had higher abundance in AD and DS compared to controls, except the APP/A beta(-X to 15) peptides which were most abundant in DS followed by controls and AD. Furthermore, the abundancies of A?X-40 and A beta X-34 were increased in DS compared with AD. A beta 1-40, A beta 1-42, and A beta 4-42 were identified as the main constitutes of protofibrils (IP'd using mAb158) and higher relative A beta 1-42 signals were obtained compared with samples IP'd with 6E10 + 4G8, indicating that the protofibrils/oligomers were enriched with peptides ending at amino acid 42. All A? peptides found in AD were also present in DS indicating similar pathways of A beta peptide production, degradation and accumulation, except for APP/A beta(-X to 15). Likewise, the A beta peptides forming protofibrils/oligomers in both AD and DS were similar, implying the possibility that treatment with clinical benefit in sporadic AD might also be beneficial for subjects with DS.
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| 3. |
- Magnusson, Kristina, et al.
(author)
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Specific Uptake of an Amyloid-beta Protofibril-Binding Antibody-Tracer in A beta PP Transgenic Mouse Brain
- 2013
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In: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 37:1, s. 29-40
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Journal article (peer-reviewed)abstract
- Evidence suggests that amyloid-beta (A beta) protofibrils/oligomers are pathogenic agents in Alzheimer's disease (AD). Unfortunately, techniques enabling quantitative estimates of these species in patients or patient samples are still rather limited. Here we describe the in vitro and ex vivo characteristics of a new antibody-based radioactive ligand, [I-125]mAb158, which binds to A beta protofibrils with high affinity. [I-125]mAb158 was specifically taken up in brain of transgenic mice expressing amyloid-beta protein precursor (A beta PP) as shown ex vivo. This was in contrast to [I-125]mAb-Ly128 which does not bind to A beta. The uptake of intraperitoneally-administered [I-125]mAb158 into the brain was age- and time-dependent, and saturable in A beta PP transgenic mice with modest A beta deposition. Brain uptake was also found in young A beta PP transgenic mice that were devoid of A beta deposits, suggesting that [I-125]mAb158 targets soluble A beta protofibrils. The radioligand was diffusely located in the parenchyma, sometimes around senile plaques and only occasionally colocalized with cerebral amyloid angiopathy. A refined iodine-124-labeled version of mAb158 with much improved blood-brain barrier passage and a shorter plasma half-life might be useful for PET imaging of A beta protofibrils.
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| 4. |
- Mcgowan, Asmaa, et al.
(author)
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Injectable Biodegradable Silica Depot for Controlled Subcutaneous Delivery of Antisense Oligonucleotides with beyond Monthly Administration
- 2023
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In: Molecular Pharmaceutics. - : AMER CHEMICAL SOC. - 1543-8384 .- 1543-8392. ; 21:1, s. 143-151
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Journal article (peer-reviewed)abstract
- Single-stranded antisense oligonucleotides (ASOs) are typically administered subcutaneously once per week or monthly. Less frequent dosing would have strong potential to improve patient convenience and increase adherence and thereby for some diseases result in more optimal therapeutic outcomes. Several technologies are available to provide sustained drug release via subcutaneous (SC) administration. ASOs have a high aqueous solubility and require relatively high doses, which limits the options available substantially. In the present work, we show that an innovative biodegradable, nonporous silica-based matrix provides zero-order release in vivo (rats) for at least 4 weeks for compositions with ASO loads of up to about 100 mg/mL (0.5 mL injection) without any sign of initial burst. This implies that administration beyond once monthly can be feasible. For higher drug loads, substantial burst release was observed during the first week. The concentrations of unconjugated ASO levels in the liver were found to be comparable to corresponding bolus doses. Additionally, infusion using a minipump shows a higher liver exposure than SC bolus administration at the same dose level and, in addition, clear mRNA knockdown and circulating protein reduction comparable to SC bolus dosing, hence suggesting productive liver uptake for a slow-release administration.
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| 5. |
- Rofo, Fadi, et al.
(author)
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Novel multivalent design of a monoclonal antibody improves binding strength to soluble aggregates of amyloid beta
- 2021
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In: Translational Neurodegeneration. - : BioMed Central (BMC). - 2047-9158. ; 10:1
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Journal article (peer-reviewed)abstract
- Background: Amyloid-beta (A beta) immunotherapy is a promising therapeutic strategy in the fight against Alzheimer's disease (AD). A number of monoclonal antibodies have entered clinical trials for AD. Some of them have failed due to the lack of efficacy or side-effects, two antibodies are currently in phase 3, and one has been approved by FDA. The soluble intermediate aggregated species of A beta, termed oligomers and protofibrils, are believed to be key pathogenic forms, responsible for synaptic and neuronal degeneration in AD. Therefore, antibodies that can strongly and selectively bind to these soluble intermediate aggregates are of great diagnostic and therapeutic interest. Methods: We designed and recombinantly produced a hexavalent antibody based on mAb158, an A beta protofibril-selective antibody. The humanized version of mAb158, lecanemab (BAN2401), is currently in phase 3 clinical trials for the treatment of AD. The new designs involved recombinantly fusing single-chain fragment variables to the N-terminal ends of mAb158 antibody. Real-time interaction analysis with LigandTracer and surface plasmon resonance were used to evaluate the kinetic binding properties of the generated antibodies to A beta protofibrils. Different ELISA setups were applied to demonstrate the binding strength of the hexavalent antibody to A beta aggregates of different sizes. Finally, the ability of the antibodies to protect cells from A beta-induced effects was evaluated by MTT assay. Results: Using real-time interaction analysis with LigandTracer, the hexavalent design promoted a 40-times enhanced binding with avidity to protofibrils, and most of the added binding strength was attributed to the reduced rate of dissociation. Furthermore, ELISA experiments demonstrated that the hexavalent design also had strong binding to small oligomers, while retaining weak and intermediate binding to monomers and insoluble fibrils. The hexavalent antibody also reduced cell death induced by a mixture of soluble A beta aggregates. Conclusion: We provide a new antibody design with increased valency to promote binding avidity to an enhanced range of sizes of A beta aggregates. This approach should be general and work for any aggregated protein or repetitive target.
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| 6. |
- Roshanbin, Sahar, 1984-, et al.
(author)
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In vivo imaging of alpha-synuclein with antibody-based PET
- 2022
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In: Neuropharmacology. - : Elsevier. - 0028-3908 .- 1873-7064. ; 208
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Journal article (peer-reviewed)abstract
- The protein alpha-synuclein (alpha SYN) plays a central role in synucleinopathies such as Parkinsons's disease (PD) and multiple system atrophy (MSA). Presently, there are no selective alpha SYN positron emission tomography (PET) radioligands that do not also show affinity to amyloid-beta (A beta). We have previously shown that radiolabeled antibodies, engineered to enter the brain via the transferrin receptor (TfR), is a promising approach for PET imaging of intrabrain targets. In this study, we used this strategy to visualize alpha SYN in the living mouse brain. Five bispecific antibodies, binding to both the murine TfR and alpha SYN were generated and radiolabeled with iodine-125 or iodine-124. All bispecific antibodies bound to alpha SYN and mTfR before and after radiolabelling in an ELISA assay, and bound to brain sections prepared from alpha SYN overexpressing mice as well as human PD- and MSA subjects, but not control tissues in autoradiography. Brain concentrations of the bispecific antibodies were be-tween 26 and 63 times higher than the unmodified IgG format 2 h post-injection, corresponding to about 1.5% of the injected dose per gram brain tissue. Additionally, intrastriatal alpha SYN fibrils were visualized with PET in an alpha SYN deposition mouse model with one of the bispecific antibodies, [I-124]RmAbSynO2-scFv8D3. However, PET images acquired in alpha SYN transgenic mice with verified brain pathology injected with [I-124]RmAbSynO2-scFv8D3 and [I-124]RmAb48-scFv8D3 showed no increase in antibody retention compared to WT mice. Despite successful imaging of deposited extracellular alpha SYN using a brain-penetrating antibody-based radioligand with no cross-specificity towards A beta, this proof-of-concept study demonstrates challenges in imaging intracellular alpha SYN inclusions present in synucleinopathies.
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| 7. |
- Söllvander, Sofia, et al.
(author)
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Accumulation of amyloid-beta by astrocytes result in enlarged endosomes and microvesicle-induced apoptosis of neurons
- 2016
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In: Molecular Neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 11
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Journal article (peer-reviewed)abstract
- Background: Despite the clear physical association between activated astrocytes and amyloid-beta (A beta) plaques, the importance of astrocytes and their therapeutic potential in Alzheimer's disease remain elusive. Soluble A beta aggregates, such as protofibrils, have been suggested to be responsible for the widespread neuronal cell death in Alzheimer's disease, but the mechanisms behind this remain unclear. Moreover, ineffective degradation is of great interest when it comes to the development and progression of neurodegeneration. Based on our previous results that astrocytes are extremely slow in degrading phagocytosed material, we hypothesized that astrocytes may be an important player in these processes. Hence, the aim of this study was to clarify the role of astrocytes in clearance, spreading and neuronal toxicity of A beta. Results: To examine the role of astrocytes in A beta pathology, we added A beta protofibrils to a co-culture system of primary neurons and glia. Our data demonstrates that astrocytes rapidly engulf large amounts of A beta protofibrils, but then store, rather than degrade the ingested material. The incomplete digestion results in a high intracellular load of toxic, partly N-terminally truncated A beta and severe lysosomal dysfunction. Moreover, secretion of microvesicles containing N-terminally truncated A beta, induce apoptosis of cortical neurons. Conclusions: Taken together, our results suggest that astrocytes play a central role in the progression of Alzheimer's disease, by accumulating and spreading toxic A beta species.
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| 8. |
- Tucker, Stina, et al.
(author)
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The Murine Version of BAN2401 (mAb158) Selectively Reduces Amyloid-beta Protofibrils in Brain and Cerebrospinal Fluid of tg-ArcSwe Mice
- 2015
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In: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 43:2, s. 575-588
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Journal article (peer-reviewed)abstract
- Amyloid-beta (A beta) immunotherapy for Alzheimer's disease (AD) has good preclinical support from transgenic mouse models and clinical data suggesting that a long-term treatment effect is possible. Soluble A beta protofibrils have been shown to exhibit neurotoxicity in vitro and in vivo, and constitute an attractive target for immunotherapy. Here, we demonstrate that the humanized antibody BAN2401 and its murine version mAb158 exhibit a strong binding preference for A beta protofibrils over A beta monomers. Further, we confirm the presence of the target by showing that both antibodies efficiently immunoprecipitate soluble A beta aggregates in human AD brain extracts. mAb158 reached the brain and reduced the brain protofibril levels by 42% in an exposure-dependent manner both after long-term and short-term treatment in tg-ArcSwe mice. Notably, a 53% reduction of protofibrils/oligomers in cerebrospinal fluid (CSF) that correlated with reduced brain protofibril levels was observed after long-term treatment, suggesting that CSF protofibrils/oligomers could be used as a potential biomarker. No change in native monomeric A beta(42) could be observed in brain TBS extracts after mAb158-treatment in tg-ArcSwe mice. By confirming the specific ability of mAb158 to selectively bind and reduce soluble A beta protofibrils, with minimal binding to A beta monomers, we provide further support in favor of its position as an attractive new candidate for AD immunotherapy. BAN2401 has undergone full phase 1 development, and available data indicate a favorable safety profile in AD patients.
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