A Human Monoclonal IgG That Binds Aβ Assemblies and Diverse Amyloids Exhibits Anti-Amyloid ActivitiesIn VitroandIn Vivo

Abstract

Alzheimer's disease (AD) and familial Danish dementia (FDD) are degenerative neurological diseases characterized by amyloid pathology. Normal human sera contain IgG antibodies that specifically bind diverse preamyloid and amyloid proteins and have shown therapeutic potential in vitro and in vivo. We cloned one of these antibodies, 3H3, from memory B cells of a healthy individual using a hybridoma method. 3H3 is an affinity-matured IgG that binds a pan-amyloid epitope, recognizing both A␤ and Ig light chain (LC) amyloids, which are associated with AD and primary amyloidosis, respectively. The pan-amyloid-binding properties of 3H3 were demonstrated using ELISA, immunohistochemical studies, and competition binding assays. Functional studies showed that 3H3 inhibits both A␤ and LC amyloid formation in vitro and abrogates disruption of hippocampal synaptic plasticity by AD-patient-derived soluble A␤ in vivo. A 3H3 single-chain variable fragment (scFv) retained the binding specificity of the 3H3 IgG and, when expressed in the brains of transgenic mice using an adeno-associated virus (AAV) vector, decreased parenchymal A␤ amyloid deposition in TgCRND8 mice and ADan (Danish Amyloid) cerebral amyloid angiopathy in the mouse model of FDD. These data indicate that naturally occurring human IgGs can recognize a conformational, amyloid-specific epitope and have potent anti-amyloid activities, providing a rationale to test their potential as antibody therapeutics for diverse neurological and other amyloid diseases.

Viral vectors for therapy of neurologic diseases

“…The most straightforward strategies have aimed at directly inhibiting the production of neurotoxic species of amyloid, either via viral vector expression of Aβ degrading enzymes, such as Neprilysin (Li et al, 2015; Lebson et al, 2010), or anti-Aβ single-chain antibodies to achieve passive immunization (Levites et al, 2015). Alternatively, targeting the cleavage of APP has been attempted, with genetic transfer of siRNA specific for β-secretase (Nawrot, 2004) or shRNA to knock-down the orphan G protein-coupled receptor that regulates activity of γ-secretase (Huang et al, 2015a), the first and second enzymes, respectively, controlling the proteolysis of APP to produce the neurotoxic amyloid peptides, respectively.…”

Salmonella Typhimurium biofilm disruption by a human antibody that binds a pan-amyloid epitope on curli

“…3H3 inhibits the fibrillization of curli. We previously observed that 3H3 inhibits polymerization of amyloid fibrils from Aβ and a lambda immunoglobulin associated with primary amyloidosis 38 .…”

“…Amyloid proteins with highly divergent sequences can share conformational epitopes that are recognizable by mAbs 49,50 . Some mAbs that bind pan-amyloid epitopes inhibit fibrillization of eukaryotic amyloids and have anti-amyloid activities in vivo 38,49,51,52 , but this has not been shown for prokaryotic amyloids.…”

“…Each of the four amyloid-binding mAbs tested here disrupted biofilm formation in vitro. 3H3 had been extensively characterized in previous studies 38 and proved most effective. 3H3 is a human mAb specific for a pan-amyloid epitope that is present on a wide variety of pathogenic human amyloids, including Aβ, immunoglobulin light chain, transthyretin, and tau 38 .…”

“…3H3 is a human mAb that preferentially binds amyloid beta protein (Aβ) oligomers and fibrils, relative to Aβ monomers, as well as many types of pathologic human amyloids, including immunoglobulin light chain and transthyretin amyloids 38 . 3H3 inhibits polymerization of Aβ and other amyloid precursors in vitro and reduces amyloid deposition in transgenic mouse models of AD and familial Danish dementia.…”