Purpose
To elucidate host immune responses to intradiscal gene transfer.
Materials and Methods
Twenty rabbits were utilized. Ad/luciferase (adenovirus construct) were injected into nucleus pulposus of lumbar vertebrae. Group 1 received intradiscal injection of Ad/luciferase only, Group 2 received subcutaneous and intradiscal injection simultaneously, Group 3 received subcutaneous injection then intradiscal injection with 2 weeks interval. Blood samples were obtained serially after injection. Animals were sacrificed at 7 weeks. Antibody to adenovirus in peripheral blood was measured with ELISA and transgene expression was measured with standard luciferase kits.
Results
All rabbits in the Group 2 and 3 exhibited increased production of neutralizing antibody. There were clearly two subgroups in Group 1, three rabbits exhibited production of antibody but remaining three rabbits showed little or no production of antibody. All rabbits showed robust increase in transgene expression regardless of titer of neutralizing antibody.
Conclusion
The intervertebral disc is favorable site for adenovirus-mediated gene transfer escaping from systemic immunity.