Fig. 2

Infusion of antibodies in different passive-transfer models causes cognitive deficits in mice. A A unilateral cannula is implanted, and patient or control IgG is infused continuously in the ventricle from day -10 to day 0. Behavioral tasks are performed. B Schematic diagram of intraventricular cannula implantation. Scale bar = 250 µm. C The novel object recognition index is lower in IgLON5-IgG-injected mice than in healthy control IgG-injected mice (t = 3.776, df = 12, p = 0.0026, unpaired t-test), and there are differences in the novel object recognition index after 30 days (t = 4.214, df = 12, p = 0.0012, unpaired t-test). D In the Y-maze, there is a reduced discrimination rate (t = 3.007, df = 12, p = 0.0109, unpaired t-test) between the two groups, and the differences persist after 30 days (t = 5.715, df = 12, p < 0.0001, unpaired t-test). E In the EPM test, there is a decrease in open arm time (t = 2.234, df = 11, p < 0.05, unpaired t-test), and the differences persist after 30 days (t = 2.833, df = 12, p = 0.0151, unpaired t-test). F There are no differences in total distance, preference index, immobile index, or time to fall. G Experimental time course of the intrahippocampal injection passive-transfer model. Stereotactic microinjections of patient or control IgG into the dorsal CA1 of the hippocampus from day -7 to day 0. Behavioral testing is performed at the indicated time points. H Schematic diagram of stereotactic injection in hippocampus. Scale bar = 200 µm. I The novel object recognition index is lower in IgLON5-IgG-injected mice than in healthy control IgG-injected mice (p = 0.0145, two-way ANOVA), and there are differences in the novel object recognition index after 30 days (p < 0.0001, two-way ANOVA). J In the Y-maze, there is a reduced discrimination rate (p = 0.0023, two-way ANOVA), and the differences persist after 30 days (p = 0.0004, two-way ANOVA). K There are no significant differences in EPM test. Statistical significance was determined using the unpaired two-tailed Student’s t-test. I and J used the repeated measure two-way ANOVA followed by Sidak’s multiple comparison test. For B–F, n = 7 per group. For G–K, n = 9 per group. For (K), n = 5 per group. *^,#p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001versus control IgG group. D = day