Figure 8.

TLR8 is expressed in developing and adult axons. (A–F) Dual-immunolabeling of TLR8 (green) and the neuronal/axonal marker βIII-tubulin (red) on sagittal sections of E18 mouse cortex. Note that TLR8 is specifically expressed in the cortical intermediate zone (IMZ) where thalamocortical and corticofugal axons are enriched. Additional zones shown in (C) include marginal zone (MZ), cortical plate (CP), ventricular zone (VZ), and lateral ventricle (V). (D–F) Corresponding higher magnification views of the IMZ regions of (A-C). (G-I) Dual-immunolabeling of TLR8 (red) and the axonal marker growth-associated protein 43 (GAP43, green) on coronal sections of E18 mouse brain. Arrowheads indicate the IMZ and arrows point to the fimbra (an axonal bundle) of the hippocampus. (J-L) Dual-immunolabeling of TLR8 (red) and the neuronal dendrite marker microtubule-associated protein 2 (MAP2, green) on sagittal sections of three-month-old mouse brain caudae/putamen, showing striatal axonal bundles, with arrowheads pointing to individual axons. Asterisks indicate neuronal somas co-stained with TLR8 and MAP2. (M-O) Dual-immunolabeling of TLR8 (red) and βIII-tubulin (green) on three-month-old mouse spinal cord sections. Note that TLR8 is highly expressed in the axons in the dorsal funiculus (arrows) and the dorsal column (asterisk).