BORNHEIM, Germany ¿ MPB Cologne GmbH filed opposition to the ¿plantibody patent¿ (EP 497 904) at the European Patent Office. The patent family covers production of glycosylated antibodies in plants.

¿We consider this platform a public domain technology,¿ MPB CEO Klaus D|ring told BioWorld International. U.S. patents on the technology in 1993 and 1997 (U.S. Patent Nos. 5,202, 422 and 5,639,947) were granted to the Scripps Research Institute, which licensed them exclusively to Epicyte Pharmaceutical Inc., both of San Diego.

¿There is plenty of scientific literature, including my own Ph.D. thesis of 1988, which constitutes prior art to the plantibody patent granted in Europe eventually in December 2000,¿ D|ring said in a prepared statement. He was first in 1988 to describe successful expression of a monoclonal antibody in transgenic tobacco, MPB said, adding that the Scripps¿ patent describes essentially the same technology. MPB also is considering taking legal action related to the U.S. patents, D|ring said.

MPB, of Cologne, aims at producing therapeutic antibodies in transgenic potato tubers on an industrial scale. Hundreds of kilograms or even tons of antibodies can be produced much cheaper than antibody fermentation by mammalian cells, the company said.

For biosafety purposes the company develops an anaerobic gene expression system for recombinant proteins in plants. It ensures that the GM potato tubers do not produce the antibodies during growth in the field. Production is switched on only by oxygen depletion. This takes place when potatoes are flooded with nitrogen in a technical containment after harvest.

D|ring founded MPB in 1998. The company to date has raised EUR11.5 million (US$10.6 million) through equity capital and public grants. It employs a staff of more than 30.