What distinguishes seed-competent tau species from non-pathogenic tau during trans-synaptic transfer?

Seed-competent tau is likely defined by a compact beta-rich conformer exposing repeat-domain surfaces, a permissive PTM barcode, and packaging into vesicles or synaptic compartments that protect it from degradation during transfer.

Uptake is not seeding. The decisive experiment must compare matched tau species that enter neurons equally but differ in templating kinetics, persistence, and downstream neurotoxicity.

Clinically, the best product concept is a conformation- or PTM-selective antibody paired with CSF seed amplification or tau-PET enrichment. Broad tau lowering risks interfering with normal microtubule biology.

Ranked synthesis: conformer exposure is primary, PTM barcode is the strongest modulator, and vesicle context explains why some transferable tau remains non-pathogenic.