DELIVERY OF HD-AD VECTORS TO PRIMATE LUNG

Texas Biomedical Research Institute, San Antonio TX

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Abstract

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In this study, baboons will be treated with a new form of gene delivery system in an attempt to produce new gene products in the cells of the airways. The gene delivery vehicle is a modified virus vector expressing common protein marker genes (beta-galactosidase (Bgal) or the baboon alpha fetoprotein (AFB) gene). Adenovirus vectors are modified versions of a common virus usually responsible for upper respiratory infections in humans. The new vector to be used in these trials has been delivered to the livers and lungs of mice, and to the livers of some primates, with very promising results. Expression of the newly introduced genes has lasted for much longer periods of time in studies with the previous vectors, and the inflammatory response has been greatly reduced. We will begin to study the use of these new vectors in the lungs, which are very complex and immunologically active organs. Animals will first be treated with a chemical agent called EGTA (n-tetra acetic acid), which relaxes in the cells of the airway surface to help them take up the virus, and then with a viral vector, which will be delivered directly to the airways using a flexible fiberoptic bronchoscope. After recovery, the animals will undergo serial chest radiographs and several blood tests, but there will be no further invasive procedures until sacrifice. The animals will be necropsied so that the location and degree of transgene expression in the lungs can be evaluated. We will also examine the animals carefully for evidence of inflammation in the lungs and regional lymph nodes, and for expression of the transgene in locations other than the lung. The use of the Bgal vector will allow us to examine the distribution of transgene expression with the greatest accuracy. AFB expressing vector will be a better indicator of vector-associated inflammation or duration of expression, and will allow us to track the true extent of vector-associated inflammation. These experiments will help determine the appropriate doses, timing and delivery methods for further preclinical and human trials of pulmonary gene delivery using these agents.