Fig. 4

Intravenously injected P2X7-blocking nbs did not cross the BBB and did not influence stroke size. C57BL6J mice intravenously received 100 μg of P2X7-specific nbs or isotype control nbs after tMCAO surgery. Twenty-four hours after stroke, lesion size was measured via MRI and TTC. Between both groups, the % of parenchymal loss in the ischemic hemisphere did not differ significantly (A; TTC: isotype n = 13 vs. P2X7-specific nb n = 7; MRI: isotype n = 8 vs. P2X7-specific nb n = 8). Statistical significance was determine by Student’s t test. B For determination of whether nbs cross the BBB, the brains of iv nb-treated mice were analyzed 24 h after treatment and stroke. After injection of 100 μg of nbs conjugated with AlexaFluor647, infiltrating macrophages (C; CD45⁺CD11b⁺Ly6C^high) were covered with P2X7-specific nbs, whereas brain resident microglia (C; CD45⁺CD11^intermedLy6C^low) did not show any P2X7-specific nb on their surface by flow cytometry. As a positive control, 0.5 μg of nb A was added ex vivo