Fig. 1
Epitope scan of TDP-43 reveals differential immunogenicity and safety in mice. Active immunization with 15 different TDP-43 peptides in wild-type C57BL/6J to select the most immunogenic ones for therapeutic vaccination in rNLS8 mice. A Localization and relative size of peptides used for active immunization targeting human TDP-43. Peptide 15 contains pS409/410. NTD: N-terminal domain, NLS: Nuclear localization signal, RRM1/2: RNA recognition motif 1/2. B Immunization regimen for wild-type C57BL/6J mice (age in weeks). Two mice per peptide antigen were immunized monthly (i1-i3) with serum collected before and in between immunizations (b0-b3). C Antibody response towards human recombinant TDP-43 (left panel) or pTDP-43 peptide (pS409/410, right panel) was determined by ELISA after three immunizations. Background-corrected optical density at 450 nm (OD450) was measured in duplicates for each animal (dots) with bars representing mean values. All sera were diluted 1:500. Preimmune serum is analyzed in Fig. S1B. D Experimental groups for therapeutic vaccination. rNLS8 animals expressing hTDP-43ΔNLS were immunized with either pooled antigens or PBS control. Monogenic littermates received either PBS (ctrl PBS) or a mixture of all peptides used for rNLS8 immunization (ctrl VAX). Peptides 1 and 3 were excluded from the control group after discovering side effects in the TDP1 + 3 group (Fig. 1F). E Timeline of immunization and blood sampling in rNLS8 and control mice. After the fifth blood sampling (b5), hTDP-43∆NLS expression was induced by removing doxycycline (DOX) from the chow. All mice were sacrificed 21 days after transgene induction (28.5 weeks of age). F Kaplan–Meier plot showing survival probability of mice during study (humane endpoint). Number of animals at the beginning of the immunization regimen is indicated. Log-rank test and pairwise comparisons with Benjamini–Hochberg correction revealed a statistically significant higher mortality in TDP1 + 3 immunized compared to TDP-PBS control mice (*, p = 0.039). Note that immunization of surviving TDP1 + 3 mice was discontinued after 1, 2 or 3 immunizations (#, dashed line)