FIGURE 2.

Vac-WT induced EAE affects both the gray and white matter in the brain parenchyma. (A–I) Sections from an intact 8.8 TCR-transgenic mouse with EAE induced by Vac-WT infection are shown from the cerebellum (A–F), hippocampal region (G), and hypothalamus (H, I) (original magnification ×20). (A) H&E analyses of a cerebellar section reveals a predominance of white matter lesions manifested as perivascular accumulations of lymphocytes. (B) Higher power magnification of the region denoted by an asterisk in (A) demonstrates the predominantly perivascular localization of lymphocytes as well as their widely scattered presence in the surrounding parenchyma. (C) IHC staining for GFAP shows increased numbers and prominence of GFAP⁺ cells associated with inflammatory foci. IHC staining for CD8 (D) and CD4 (E) demonstrates a preponderance of CD8 T cells both in perivascular spaces and widely scattered in the tissue parenchyma, with fewer numbers of intermixed CD4⁺ cells. (F) IHC staining for MBP in the same region as (D) demonstrates an absence of lesion-associated demyelination. (G) H&E staining of the hippocampal region, another primary site of involvement, reveals histologically mild, mostly perivascular lesions (arrow). (H) H&E staining in the hypothalamic region shows mild lesions with scattered lymphoid cells similar to those seen in the cerebellum. (I) IHC staining for CD8 demonstrates that many of the lymphoid cells in the hypothalamic region are CD8 T cells.