Fig. 4.
Pericyte-deficient mice die with atypical EAE accompanied by increased leukocyte infiltration into the brain. (A) Kaplan–Meier survival curves after active induction of EAE. The experiment was terminated on day 15, indicated by black dashed line. Pooled data from two individual experiments (n = 11 mice per genotype). Survival curves showed statistical difference (P < 0.0001, log-rank test). (B) Scoring of neurological symptoms during the course of active EAE. The left y axis shows cerebellar ataxia scores of Pdgfbret/ret mice (in red), and the right y axis shows classical EAE scores of control mice (in black). Arrowheads indicate when individual mice were euthanized for flow-cytometry analysis. Materials and Methods includes detailed termination criteria. Each line represents symptoms of an individual mouse (n = 5 mice per genotype, showing two pooled experiments). (C) Kaplan–Meier survival curves after passive induction of EAE. The experiment was terminated on day 14, indicated by black dashed line (controls, n = 5; Pdgfbret/ret, n = 6). Survival curves showed a statistically significant difference (P = 0.0300, log-rank test). (D) Immunohistochemical staining of T cells (CD3, in red) of sagittal brain sections of the cerebellum and brainstem after active induction of EAE of control (on day 16 postimmunization) and Pdgfbret/ret mice (on day 11 postimmunization). (E) Immunohistochemical staining of T cells (CD3, in red) on coronal sections of the spinal cords showing two regions (1, 2) after active induction of EAE in control (on day 16 postimmunization) and Pdgfbret/ret mice (on day 11 postimmunization). Tissue sections were counterstained with hematoxylin (D and E). (F and G) Quantification of the absolute cell numbers of different leukocyte populations (gated as shown in SI Appendix, Fig. S10) in the brains (cerebrum, cerebellum, and brainstem; F) and spinal cords (G) of control (EAE score of 3–3.5) and Pdgfbret/ret (ataxia score, n = 9–10) mice using flow cytometry. Shown are pooled data from two individual experiments (n = 5 mice per genotype). Data are presented as the mean ± SD. Statistical significance was determined using unpaired t test (brain, CD45hi, MdCs, and CD4+ T and CD8+ T cells; spinal cord, CD4+ T and Ly6Chi monocytes) or Mann–Whitney U test (brain, Ly6Chi monocytes; spinal cord, CD45hi, CD8+ T cells, and MdCs). (Scale bars: D and E, 100 µm.)