FIG. 7.

Neutralizing antibodies and surfactant dilution. Eleven months after the initial marker gene injection with various serotypes in the left stifle (previously injected serotype along the x-axis), the rats used for in vivo bioluminescence imaging were reinjected with 1.0×10¹⁰ genome copies of vector serotype 2/5 in the right stifle. For this experiment, the injected vector was diluted with either saline or surfactant (0.01% final surfactant [F68] concentration). Unfortunately, not all animals initially injected with the various serotypes were available for the second injection 11 months later. For serotype 2/9 animals, three were reinjected with serotype 2/5 vector diluted with saline and two with vector diluted with surfactant. For serotype 2/8 animals, one was reinjected with vector diluted with saline and two with vector diluted with surfactant. For serotype 2/5 animals, two were reinjected with vector diluted with saline and one with vector diluted with surfactant, and for serotype 2/2 animals, one was reinjected with vector diluted with saline and two with vector diluted with surfactant. These results reflect what has been observed when using surfactant supplementation in other animal models, and the use of surfactant supplementation has become standard practice in our laboratory. No transduction in the right stifle was observed in rats previously injected in the left stifle with serotype 2/5.