Fig. 4

CA-tau structures are present in human CSF. A Representative brightfield image of CA in the hippocampal sulcus of AD patient tissue section. Inset (dashed box) centered on a CA in the glia limitans ensheathed in AT8⁺ processes on the edge of the parenchyma. Scale bar = 50 µm. B Representative immunofluorescent confocal image of CA in the hippocampal sulcus of AD patient tissue section stained with GFAP (grey), Tau-1 (red), and IgM (green). Nuclei stained with DAPI (blue). Inset (dashed box) centered on Tau-1-immunoreactive CA in the glia limitans ensheathed in GFAP⁺ processes on the edge of the parenchyma. Scale bar = 50 µm. C Representative immunofluorescent confocal images of CSF containing CA were stained with Tau5 IgG1 (red) and IgM (green) and subsequently imaged at 120× magnification. Scale bar = 50 µm (i) 20 µm (ii–v). Maximum intensity z-projection frames are shown in panels i and v, higher magnification inset frames are shown in panels ii-iv, and single plane inset frames are shown in panels vi–viii. D Representative immunofluorescent confocal images of CA present in CSF that were pre-digested with amylo-glucosidase were imaged at 20× magnification to detect Tau5 IgG1 (red) and IgM (green, brightness increased for visualization). Scale bar = 500 µm (top row), 10 µm (bottom row)