in-vitro-assay-for-studying-aggregation-tau-protein-drug

<em>In Vitro</em> Assay for Studying the Aggregation of Tau Protein and Drug Screening

Aggregation of tau protein and formation of paired helical filaments is a hallmark of Alzheimer&#39;s disease and other tauopathies. Compared to other ...

cell-based-assay-to-study-antibody-mediated-tau-clearance-by-microglia

Cell-based Assay to Study Antibody-mediated Tau Clearance by Microglia

Alzheimer&#39;s disease (AD) is a progressive neurodegenerative condition in which aggregated tau and amyloid proteins accumulate in the brain causing ...

Janssen Pharmaceutical Companies of Johnson and Johnson

Janssen Pharmaceutical Company of Johnson & Johnson, The Netherlands

Misfolding and aggregation of tau protein are closely associated with the onset and progression of Alzheimer's Disease (AD). By interrogating IgG memory B cells from asymptomatic donors with tau peptides, we have identified two somatically mutated V5-51/V4-1 antibodies. One of these, CBTAU-27.1, binds to the aggregation motif in the R3 repeat domain and blocks the aggregation of tau into paired helical filaments (PHFs) by sequestering monomeric tau. The other, CBTAU-28.1, binds to the N-terminal insert region and inhibits the spreading of tau seeds and mediates the uptake of tau aggregates into microglia by binding PHFs. Crystal structures revealed that the combination of V5-51 and V4-1 recognizes a common Pro-X-Lys motif driven by germline-encoded hotspot interactions while the specificity and thereby functionality of the antibodies are defined by the CDR3 regions. Affinity improvement led to improvement in functionality, identifying their epitopes as new targets for therapy and prevention of AD.

A common antigenic motif recognized by naturally occurring human V5-51/V4-1 anti-tau antibodies with distinct functionalities.

Aggregation of tau protein and spreading of tau aggregates are pivotal pathological processes in a range of neurological disorders. Accumulating evidence suggests that immunotherapy targeting tau may be a viable therapeutic strategy. We have previously described the isolation of antibody CBTAU-22.1 from the memory B-cell repertoire of healthy human donors. CBTAU-22.1 was shown to specifically bind a disease-associated phosphorylated epitope in the C-terminus of tau (Ser) and to be able to inhibit the spreading of pathological tau aggregates from P301S spinal cord lysates in vitro, albeit with limited potency. Using a combination of rational design and random mutagenesis we have derived a variant antibody with improved affinity while maintaining the specificity of the parental antibody. This affinity improved antibody showed greatly enhanced potency in a cell-based immunodepletion assay using paired helical filaments (PHFs) derived from human Alzheimer's disease (AD) brain tissue. Moreover, the affinity improved antibody limits the in vitro aggregation propensity of full length tau species specifically phosphorylated at position 422 produced by employing a native chemical ligation approach. Together, these results indicate that in addition to being able to inhibit the spreading of pathological tau aggregates, the matured antibody can potentially also interfere with the nucleation of tau which is believed to be the first step of the pathogenic process. Finally, the functionality in a P301L transgenic mice co-injection model highlights the therapeutic potential of human antibody dmCBTAU-22.1.

Rosa Crespo

Janssen Prevention Center

Janssen Pharmaceutical Companies of Johnson and Johnson

In Vitro Assay for Studying the Aggregation of Tau Protein and Drug Screening

Cell-based Assay to Study Antibody-mediated Tau Clearance by Microglia

Rosa Crespo

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Janssen Pharmaceutical Companies of Johnson and Johnson

In Vitro Assay for Studying the Aggregation of Tau Protein and Drug Screening

Cell-based Assay to Study Antibody-mediated Tau Clearance by Microglia

Janssen Prevention Center