Extended Data Fig. 9: Consecutive T_β-syn cell attacks result in cortical grey matter degeneration.

a, Relapsing-remitting clinical disease bouts induced by repeated T_β-syn cell transfer. Clinical score (bars) and relative weight changes (lines) in transgenic rats transferred four consecutive times with T_β-syn or T_OVA cells. Data are mean ± s.e.m. Representative data of four independent experiments. b, Consecutive T_β-syn-cell-mediated grey matter inflammation induces reiterated episodes of BBB leakage. Quantification of Gd enhancement in the indicated brain compartments performed on T1-weighted MRI images acquired at the onset of disease after the first and fourth T cell transfer. Each line represents one individual rat. Representative data of 2 independent experiments (n = 5 per group per experiment). c, Relapsing-remitting clinical disease bouts induced by repeated T_MBP cell transfer. Clinical score (bars) and relative weight changes (lines) in transgenic rats transferred four consecutive times with T_MBP cells. Data are mean ± s.e.m. d, T_MBP-cell-induced disease bouts do not cause BBB leakage. Quantification of Gd enhancement in the indicated brain compartments performed as in b. e–i, Repeated T_β-syn-cell-induced autoimmune inflammation induces long-term damage in the cortical grey matter. Rats were transferred four times with T_β-syn or T_OVA cells. Histological analysis of the cerebral cortex was performed three weeks after the peak of the fourth disease bout. e, Very few residual immune infiltrates are detectable in the recovery stage of relapsing grey matter disease. Top, representative haematoxylin and eosin (HE)-stained coronal paraffin sections of brain cortex showing the presence of very limited infiltrates in the leptomeninges (arrows) of a 4× T_β-syn cell-transferred rat. Note, however, the thickened leptomeninges, increased vascularization (V) in the cortical layer I (I) and enrichment of cells with small nuclei, representing microglia (examples shown by arrowheads). Bottom, representative CD43 (W3/13) staining on frozen sections of 4× T_OVA and 4× T_β-syn cell-transferred rats. The latter shows few CD43⁺ lymphocytes within the leptomeninges (arrows) and around cortical vessels (arrowheads). f, Persistent grey matter gliosis induced by 4× T_β-syn cell transfer. Confocal images of cortical tissue stained with anti-IBA1 (left) or anti-GFAP antibodies (right). g, Rarefaction and disarrangement of neuronal processes. Representative neurofilament stainings of cortical grey matter on 4× T_β-syn or 4× T_OVA-cell-transferred rats. In corresponding regions of the motor cortex, the thickness, length and number of straight filaments (arrowheads) are reduced in rats that have received 4× T_β-syn cells. h, i, Repeated episodes of grey matter inflammation do not affect white matter thickness. h, Histological analysis of corpus callosum thickness. Mean corpus callosum thickness across all control samples for the analysed anterior–posterior interval was set to 100%. Each data point represents relative corpus callosum thickness for one individual rat measured at the indicated distance to bregma. Lines represent fitting curves (shading, 95% confidence interval) for the respective group of rats. n = 8 for control, n = 6 for 4× T_β-syn group from 4 independent experiments. Unpaired two-tailed t-test. i, Corpus callosum thickness determined by longitudinal MRI analysis at the indicated time over the disease course. Each line represents one individual rat. Representative data of 2 independent experiments (n = 5 per group per experiment). j, k, Enlargement of the ventricle size induced by relapsing autoimmune grey matter disease. j, Representative z projection of MRI images at the indicated time points after the first and fourth transfer of T_β-syn or T_OVA cells. k, Quantification of changes in ventricular volume over time. Representative data of 2 independent experiments (n = 5 per group per experiment). b, i, k, Two-way ANOVA with Bonferroni’s multiple comparison correction. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.