Figure 6.

IHC assessment of antibody delivery to the brain parenchyma using the TXB4 shuttle. Mice were dosed with either the TXB4-PD-L1 fusion or unmodified antibody at 25 nmol/kg, IV and brains were collected following cardiac perfusion 18 h post injection (n = 2). Brain sections were stained for the presence of exogenous antibodies via IHC and images were collected from representative regions for comparison. Sections taken from the thalamus showed the distribution of the (a) PD-L1 antibody versus (b) TXB4-PD-L1. Prominent neuronal staining was only observed with the antibody fused to the shuttle. Pronounced TXB4-PD-L1 staining was seen in trigeminal neurons in the midbrain (d) and Purkinje cells in cerebellum (f), where diffuse parenchymal staining and BCEC staining were clearly distinguishable; PD-L1 antibody showed no staining in corresponding sections (c,e). Scale bars at 50 μm.