This viral vector core function is to provide each of the three projects two major services: (1) Design and construction of enhancer/promoters and transgenes for packaging within viral vectors; (2) Production, purification and testing of those viral vector types. Design and construction of packaging plasmids include: A) Each viral vector has specific design requirements including packaging capacity, serotype and pseudotype recommendations, these will be examined prior to construction of each new packaging plasmid. B) The construction of each packaging plasmid will be confirmed by restriction digests and sequencing, and then appropriately tested for transgene expression. Production, purification and testing include: A) Production of: - / AV serotypes 1-9 - Adenovirus type 2 - VSVG pseudotyped Lentivirus B) Purification of / AV will depend on serotype. AAV serotypes 1-8 have been purified by iodixanol gradient centrifugation then fast protein liquid chromatography (FPLC), followed by dialysis. / AV9 has been purified by polyethylene glycol precipitation, then a cesium step gradient then a cesium continuous gradient, followed by dialysis. For each of these purification methods we have used transgene primers and real-time PCR to quantify the titer of the virus. To examine the purity of the virus we use silver staining of SDS polyacrylamide gels. To test for biological contaminants we add aliquots ofthe purified virus to cells in culture without antibiotics. Experience has demonstrated that if the number of viral particles obtained from each cell is less than 5000 for / AV then the prep will be discarded. While 5000 virions/cell in a 2 x 109 cell preparation will produce 1 x 1013 particles these preps do not perform well in vitro or in vivo. For the purification of Adenovirus we use two methods. First the traditional method of cesium step gradient then by continuous cesium gradient, followed by dialysis. The second approach uses commercial column purification methods from Vivapure AdenoPACK kits (Goettingen, Germany). We have utilized the UV absorption for quantification (Liebermann and Mental 1994), as well as real time PCR. The purification of lentivirus utilizes a sucrose cushion gradient. In addition there are a number of commercially available lentivirus concentration and purification kits (Cell Biolabs; San Diego, CA). C) Testing of each virus that will include: i) Titration of the viruses after dialysis prior to delivery to project leaders. ii) Testing of the in vitro transduction efficiency of viruses in HeLa cells for CMV or other strong promoters, or primary neonatal rat cardiomyocytes for restricted (cardiac) promoters. iii) Western blot analysis will be used to establish expression of viral transgenes prior to delivery to project leaders. This core will manufacture and purify AAV serotypes 1-9, Adenovirus type 2 and Lentivirus. Specifically, we will develop and maintain cell lines for large scale production (100-200 of 15-cm plate range) of specific vectors and transgenes as dictated by PPG participant needs. We will provide the molecular biological support related to sub-cloning of novel therapeutic genes, inhibitory and micro RNAs, as well as enhancer-promoter configurations for viral development as needed by the Project Leaders. The main functions of Core D are; 1) Production of Adeno- and Adeno-associated viruses, 2) Purification of these viruses, and 3) Testing viruses prior to transferring to members of the Scientific Program. An additional function will be the production of VSVG pseudotyped lentivirus, as needed by members ofthe Scientific Program.
The viral vector production core performs a service for each of the project leaders. We will provide high quality, purified recombinant viruses that contain transgenes which have been shown to improve heart function in small animal models of heart failure. Heart failure affects millions of Americans and our goal is to improve the condition of suffering individuals through viral vector based therapeutics.
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