Characterization of adenovirus p21 gene transfer, biodistribution, and immune response after local ocular delivery in New Zealand white rabbits

Exp Eye Res. 2003 Sep;77(3):355-65. doi: 10.1016/s0014-4835(03)00122-2.


Previous studies suggest that local gene therapy with rAd-p21(WAF1/Cip-1) [. Arch. Ophthalmol. 120, (2002) 941-949] may provide an effective adjunctive anti-proliferative treatment to prevent glaucoma surgery failure. To further investigate rAd-p21 in this indication, we have characterized several parameters of local gene delivery to conjunctiva including, vector delivery and transgene expression in target tissue, inflammatory response, biodistribution to non-target tissues, and immune response. Quantitative PCR and RT-PCR assays were employed to evaluate rAd-p21 dissemination and gene transfer following a single subconjunctival injection. In target tissue, significant levels of rAd-p21 DNA were found in 6/6 animals 1 and 4 days after injection. rAd-p21 DNA and RNA could be detected in the un-injected contralateral eye but at levels that were 10000-100000 lower than in the injected eye. Expression of human p21 transgene in conjunctival fibroblasts was confirmed by immunohistochemistry. Biodistribution of rAd-p21 following subconjunctival injection was substantially limited to ocular tissue. In 1/6 rabbits, rAd-p21 DNA was found in whole blood, liver, and spleen at levels that were barely detectable. All non-target organs were negative on day 4. In contrast, in a rabbit injected intravenously as a positive control, all blood samples and tissues samples were positive. rAd-p21 delivery to conjunctiva followed by filtration surgery caused an early acute inflammatory response, which by day 14 was indistinguishable from placebo-treated eyes. Neutralizing anti-adenovirus antibodies were detected following administration of rAd-p21 to conjunctiva, however, vector delivery and transgene expression were unaffected in a subsequent administration to the contralateral eye in the same animal. These results show that local delivery to conjunctiva may be a suitable delivery mode for ocular gene therapy.

MeSH terms

  • Adenoviridae / genetics*
  • Adenoviridae / immunology
  • Animals
  • Antibodies, Viral / immunology
  • Conjunctiva / physiology*
  • DNA, Viral / analysis
  • Gene Expression / genetics
  • Gene Transfer Techniques*
  • Genetic Vectors / genetics
  • Glaucoma / surgery
  • Humans
  • Immunohistochemistry / methods
  • Inflammation / immunology
  • Injections
  • Liver / metabolism
  • Polymerase Chain Reaction / methods
  • RNA, Viral / analysis
  • Rabbits
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Spleen / metabolism
  • Time Factors
  • Transgenes / genetics


  • Antibodies, Viral
  • DNA, Viral
  • RNA, Viral