1. ¹Gene Therapy Research Group, Department of Cell and Molecular Biology, SAF Building, Imperial College, South Kensington, London SW7 2AZ, United Kingdom
2. ²Leukocyte Biology, Department of Cell and Molecular Biology, SAF Building, Imperial College, South Kensington, London SW7 2AZ, United Kingdom
3. ³Childrens Hospital, University of Erlangen, Loschgetr, 15, D-91054 Erlangen, Germany

Correspondence: S. M. K. Buckley, To whom correspondence and reprint requests should be addressed.

Received 9 December 2004; Accepted 22 February 2005.

Abstract

Intra-amniotic injection of adenovirus allows transduction of the fetal airways following natural fetal breathing movements. This administration method is promising for use in gene therapy for cystic fibrosis and other diseases for which the main target for exogenous gene expression is the lung. Here we have investigated factors that may affect the efficacy of gene transfer to the murine fetal lung. We examined marker compound distribution and transgene expression (from a first-generation adenoviral vector) at different stages of development. This demonstrated that fetal breathing movements at 15–16 days of gestation are of sufficient intensity to carry marker/vector into the fetal lungs. These movements can be significantly stimulated by the combination of intra-amniotic theophylline administration and postoperative exposure of the dam to elevated CO₂ levels. However, the most important factor for efficient and consistent pulmonary transgene delivery is the dose of adenoviral vector used, as both the degree of transduction and the percentage of lungs transduced increases with escalating viral dose.