Therion Biologics Corp. announced that it has added two morepox virus vectors to its arsenal of vector systems for producinghuman vaccines.
Privately held Therion of Cambridge, Mass., acquired from theUniversity of Florida Research Foundation Inc. exclusiveworldwide rights to pending patents on the use of swine pox asa vector and to an expression system based on the entomopox(insect) virus.
Under the agreement with the University of Florida,Gainesville, Therion will also support professor Richard Moyer'scontinuing research on poxvirus vector technology. Moyer,chairman of the department of immunology and medicalmicrobiology at UF's College of Medicine, has pioneered the useof swine pox and entomopox as vectors and protein expressionsystems.
Therion has already developed vaccinia virus (cow pox) vectorsfor use as live recombinant vaccines, as well as vectors fromfowl pox.
Although the various viral vectors are all host-range-restricted,they are similar enough in basic morphology and structure that"similar technologies can be used to engineer them" to containthe foreign gene or genes of interest, explained Dennis Panicali,the president and chief executive officer of Therion. "They areall large DNA viruses that can contain multiple genes," headded.
But each viral vector has "unique properties and advantages,"which makes it possible for Therion to customize its live viralvectors for particular applications, Panicali told BioWorld.
For instance, "swine pox can replicate in mammalian cells, butonly slowly and in certain continuous cell lines." Because theexpression levels are good and can be maintained for longperiods of time, such systems are good for manufacturingpurposes, Panicali said. And entomopox viruses have strongpromoters that can achieve high levels of expression.
In fact, it's possible to "mix and match the promoters tooptimize expression," he added, thus generating "liverecombinant viral vector products with the potential forenhanced safety and broad immunotherapy applications."
The first target for Therion's immunotherapeutics is cancer.
Therion Biologics was spun off from the former AppliedbioTechnology Inc. (ABT) in July 1991, when Oncogene ScienceInc. (NASDAQ: ONCS) acquired the cancer therapy anddiagnostics components of ABT in a stock deal valued at about$10.5 million.
Therion attempted twice to go public -- most recently in July1992 -- but withdrew its stock offering and has been raisingmoney privately since then, Panicali said.
-- Jennifer Van Brunt Senior Editor
(c) 1997 American Health Consultants. All rights reserved.