Figure 4. Injection of FIV(lacZ) into the right TMJ (5 x 10⁶ infectious particles) resulted in successful transduction of primary sensory neurons with the reporter gene β-galactosidase in trigeminal ganglia ispilateral to the treated joint. (A) β-galactosidase expression was detected by X-gal histochemistry in sagittal sections of the right-side ganglion (4X), (B) primarily at its posterior and posterolateral regions (20X). (C) Injection of FIV('lac) did not result in β-galactosidase expression. (D) The X-gal staining was confirmed with immunocytochemistry, with the use of antibodies raised against bacterial β-galactosidase following FIV(lacZ) injection compared with (E) FIV('lac) treatment.