A shorter linker in the bispecific antibody RmAb158-scFv8D3 improves TfR-mediated blood-brain barrier transcytosis in vitro.

Transferrin Receptor (TfR)-mediated transcytosis across the blood-brain barrier (BBB) enables the uptake of bispecific therapeutic antibodies into the brain. At therapeutically relevant concentrations, bivalent binding to TfR appears to reduce the transcytosis efficiency by receptor crosslinking. In this study, we aimed to improve BBB transcytosis of symmetric antibodies through minimizing their ability to cause TfR crosslinking.

Multivalent design of the monoclonal SynO2 antibody improves binding strength to soluble α-Synuclein aggregates.

Soluble aggregates are reported to be the most neurotoxic species of α-Synuclein (αSyn) in Parkinson's disease (PD) and hence are a promising target for diagnosis and treatment of PD. However, the predominantly intracellular location of αSyn limits its accessibility, especially for antibody-based molecules and prompts the need for exceptionally strong soluble αSyn aggregate binders to enhance their sensitivity and efficacy for targeting the extracellular αSyn pool. In this study, we have created the multivalent antibodies TetraSynO2 and HexaSynO2, derived from the αSyn oligomer-specific antibody SynO2, to increase avidity binding to soluble αSyn aggregate species through more binding sites in close proximity.

Standardized Preclinical Blood-Brain Barrier Mouse Assay Validates Endocytosis-Dependent Antibody Transcytosis Using Transferrin-Receptor-Mediated Pathways.

The presence of the blood-brain barrier (BBB) creates a nigh-on impenetrable obstacle for large macromolecular therapeutics that need to be delivered to the brain milieu to treat neurological disorders. To overcome this, one of the strategies used is to bypass the barrier with what is referred to as a "Trojan Horse" strategy, where therapeutics are designed to use endogenous receptor-mediated pathways to piggyback their way through the BBB. Even though methodologies are commonly used to test the efficacy of BBB-penetrating biologics, comparable BBB models are in high demand, as they benefit from being an isolated cellular system devoid of physiological factors that can on occasion mask the processes behind BBB transport via transcytosis.

A single-chain fragment constant design enables easy production of a monovalent blood-brain barrier transporter and provides an improved brain uptake at elevated doses.

The interest for developing antibody-driven therapeutic interventions has exponentially grown over the last few decades. Even though there have been promising leaps in the development of efficacious antibody therapies, problems revolving around production and site-directed delivery of these large macromolecules persist. This is especially pertinent when it comes to designing and producing antibodies to penetrate the blood-brain barrier (BBB) to tackle neurodegenerative diseases.

Introducing or removing heparan sulfate binding sites does not alter brain uptake of the blood-brain barrier shuttle scFv8D3.

The blood-brain barrier (BBB) greatly limits the delivery of protein-based drugs into the brain and is a major obstacle for the treatment of brain disorders. Targeting the transferrin receptor (TfR) is a strategy for transporting protein-based drugs into the brain, which can be utilized by using TfR-binding BBB transporters, such as the TfR-binding antibody 8D3. In this current study, we investigated if binding to heparan sulfate (HS) contributes to the brain uptake of a single chain fragment variable of 8D3 (scFv8D3).

A Brain-Targeting Bispecific-Multivalent Antibody Clears Soluble Amyloid-Beta Aggregates in Alzheimer's Disease Mice.

Amyloid-β (Aβ) oligomers and protofibrils are suggested to be the most neurotoxic Aβ species in Alzheimer's disease (AD). Hence, antibodies with strong and selective binding to these soluble Aβ aggregates are of therapeutic potential. We have recently introduced HexaRmAb158, a multivalent antibody with additional Aβ-binding sites in the form of single-chain fragment variables (scFv) on the N-terminal ends of Aβ protofibril selective antibody (RmAb158).