Fig. 2

Increased expression of CXCL13 on ICAM-1⁺ cerebral blood vessels leads to accelerated CD4 + CXCR5 + cell infiltration in the ipsilateral brain hemisphere after tMCAO. a Representative images of immunohistochemistry (IHC) staining of mouse brains with anti-ICAM-1 (green), and anti-CXCL13 (red) antibodies, and merged image (right panel) of cerebral blood vessels in ipsilateral brain hemisphere following SHAM conditions, as well as at 4 h and 24 h post-tMCAO. b Quantification of ICAM-1+ area in ipsilateral brain hemisphere following SHAM conditions, as well as at 4 h and 24 h post-tMCAO (n = 5). c Quantification of percentage area of ICAM-1+ vessels that are also CXCL13+ in ipsilateral brain hemisphere following SHAM conditions, at 4 h post-tMCAO and at 24 h post-MCAO in mice (n = 5). d Representative low (top panels) and high (bottom panels) magnification images of CD4 (green), CXCR5 (red), and CXCL13 (cyan) IHC staining at the peri-infarct area, 4 h post-tMCAO. Bottom panels are a higher magnification image of the dotted box from the top panel to highlight double-positive CD4+ CXCR5+ T cells indicated by orange arrows. Scale bar = 30 μm. e–g Quantification of CD4+ T cells (e), percentage of CD4+ T cells positive for CXCR5 (f), and percentage of CXCR5+ cells positive for CD4 (g) in the contralateral caudate, ipsilateral caudate/thalamus and ipsilateral cortex. Data are combined from three independent experiments. Data represent mean ± s.e.m. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. n.s. = not significant. One-way ANOVA followed by Dunn’s post hoc test (b, c, e, f, g)