PPL Therapeutics develops technique for birth of transgenic sheep with 'targeted' gene.
The new technology, for which PPL has filed patent applications, has immediate utility in some of PPL's existing product development programs, but it also has broader implications and uses outside the company's core areas of interest, which will provide the potential for PPL to generate licensing income in the future.
PPL's gene targeting technique involves introducing a gene at a specific place in the chromosomes of livestock cells in culture. Offspring carrying the desired changes are then produced from these cells using nuclear transfer (the technique used by PPL and the Roslin Institute to produce Dolly). Previously, it was only possible to add new genes, but not replace or inactivate ("switch off") existing ones. Also, the site of addition of a gene was previously entirely random and in a different place for every new transgenic animal.
The benefits to PPL of this new technology are numerous. For example, it will allow a chosen gene for a therapeutic protein to be inserted at a specific chromosomal site selected for its ability to facilitate high expression from any inserted gene. The ability to enhance expression will greatly accelerate PPL's capacity to produce therapeutic and nutritional proteins in the milk of transgenic livestock.
Dr Ron James, managing director of PPL said: "This is a major technical breakthrough and again shows the application of pioneering science by PPL. The real importance, however, lies in the potential application of the technique to provide PPL with therapeutic products for clinical trials more quickly and with more certainty."
PPL now intends to apply the new technology to the replacement of specific genes with their human equivalent. For example, replacing the bovine version of serum albumin with the human form (an undertaking which was previously impossible) will enable the cost effective production of human serum albumin in the milk of cows. PPL will incorporate the new technology into its existing human serum albumin program. Human serum albumin, which is used in the treatment of burns and other traumatic injury, is currently produced from human plasma. PPL believes that cost effective production in transgenic cows will only be possible if the human albumin gene is substituted for the bovine albumin gene.
Dr Alan Colman, research director of PPL said: "The range of applications for gene targeting is huge and could bring very real benefits for human healthcare. For PPL, gene targeting and its applications was one of the key reasons for our involvement in nuclear transfer, commonly referred to as cloning, in livestock."
In the longer term, and beyond the application of gene targeting for protein production, the new technology might be applied to situations in which it is necessary to inactivate (or "switch off") genes. Within PPL's product portfolio, xenotransplantation is one such area where the inactivation of a specific gene could lead to pig organs being more readily accepted by the human immune system, allowing transplantation of animal organs to take place where human organs are unavailable. PPL has already used its gene targeting technology to inactivate the relevant gene in cultured pig cells.
For areas outside its core areas of interest, PPL will seek to license the new technology to other scientists and companies, allowing many people to benefit from its research and also to generate further revenue streams for PPL.
PPL Therapeutics is a biopharmaceutical company which is one of the world's leaders in the application of transgenic animal technologies to the development and production of human proteins for therapeutic and nutritional applications.
PPL has a broad pipeline of diverse protein products including AAT, the company's lead product, which is currently in Phase II clinical trials for cystic fibrosis. AAT is also under development for the treatment of congenital deficiency. PPL's other lead products are fibrinogen and bile salt stimulated lipase.
Transgenic production of human proteins involves the introduction of copies of human DNA into the genetic material of another species. The resulting transgenic animals express the human gene product (protein) in the mammary gland allowing its collection and purification during lactation. The technique offers the opportunity to produce human proteins economically and in potentially unlimited quantities.
PPL has a world wide exclusive license from the Roslin Institute to use the Institute's intellectual property relating to nuclear transfer (cloning) in the field of production of proteins for pharmaceutical and nutraceutical use in the milk of ruminant livestock and rabbits.
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|Comment:||PPL Therapeutics develops technique for birth of transgenic sheep with 'targeted' gene.|
|Publication:||BIOTECH Patent News|
|Date:||Jul 1, 1999|
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