Zynaxis Cell Science Inc. has begun sales to the researchcommunity of a versatile radioactive-tagged cell tracking kitthat can be used to target all living cells.
The PKH95-I125 Cell Linker Kit (PKH95) consists of an iodine-125 radionuclide joined to Zynaxis' proprietary cell linkermolecule. The molecule, called a Zyn-linker, is an organiccompound with hydrophilic tails that insert themselves intothe lipid (fat) portion of a cell's membrane.
Since many linkers can insert themselves into a cell'smembrane without disrupting the cell's function, researcherscan place many labels on living cells, making them easier tostudy. For example, scientists can watch how red and whiteblood cells move through the body.
Also, since all cellular membranes contain lipids, all cells canbe targeted using this technology.
Other methods of targeting cells include the use of radio-labelled antibodies to target proteins on a cell's surface. Theyare limited by the number and kinds of proteins on the cell.
The market for PKH95 is about $5 million, said Thomas CekoricJr., Zynaxis' president and chief executive officer. The companyalso sells two kits, PKH2 and PKH26, with fluorescent tagsattached to Zyn-linkers. Zynaxis sells the kits directly in theUnited States and through distributors in Japan and Europe.
The cell tracking kits are an offshoot of Zynaxis' mainbusiness of using Zyn-linkers to deliver imaging agents ordrugs directly to diseased cells, such as tumors or tissuesdamaged by rheumatoid arthritis or cardiovascular problems.An advantage of the technology is that it can deliver a higherpayload per cell, said Cekoric. Once in the cell's membrane, thelinker remains there. Animal studies have indicated that thelinkers are nontoxic and nonimmunogenic, he added.
Cekoric told BioWorld that Zynaxis recently received a smallbusiness innovation research Phase I grant for $50,000 tocouple anti-clotting agents, such as hirudin, to solid surfaces,such as the stainless steel-based devices used to openarteries. The agents would prevent the formation of new bloodclots in treated arteries. The Malvern, Pa., company already hasa $500,000 SBIR Phase II grant to target its Zyn-linkertechnology to tumors.
Zynaxis, founded in 1988, is primarily venture capital-financed, said Cekoric, who joined Zynaxis two months ago. Hepreviously was president of API and Oxford Labware Divisionsof Sherwood Medical/American Home Products. -- CarolTalkington Verser, Ph.D.
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