Coinciding with the publication of its landmark study describing cancer vaccine production in plants, Biosource Technologies announces today the launch of its new Antigenics Division to provide tools to increase the speed and productivity of vaccine research and development programs.

The article published today in the Proceedings of the National Academy of Sciences (PNAS)
describes the production for the first time of a protein-based tumor-specific vaccine for the
treatment of malignancies using a novel plant-based transient expression system (McCormick et
al., 1999; PNAS 96(2):703-708). In the report, a collaborative team led by Dr. Daniel Tuse at
Biosource and by Dr. Ronald Levy at Stanford University describes a strategy for individualized
treatment of indolent non-Hodgkin's lymphoma (NHL) in a mouse model system.

The groundbreaking study shows that mice vaccinated with a plant-produced soluble protein
from an individual tumor cell generated a potent and highly specific immune response that
protected the mice from a lethal challenge of an injected mouse B-cell lymphoma. Whereas all
mice that were not vaccinated died within 3 weeks of lymphoma injection, 80% of vaccinated
mice were protected and survived. NHL is the most predominant type of lymphoma and is the
sixth most common cause of cancer-related deaths. More than 55,000 new cases of NHL are
expected in the United States this year, and at least one-third of those may be eligible for
vaccination therapy. Biosource is developing rapid techniques to produce vaccines for human
NHL epitope sequences that the Company obtains from Dr. Ronald Levy at Stanford
University -- one of the premier clinical treatment and pioneering research centers for NHL
immunotherapy.

Biosource created Biosource Antigenics to focus initially on the NHL vaccine as a target that is
well-suited to demonstrate that its plant-based transient expression system can address the
needs of vaccine research and development programs. NHL is characterized by its extreme
diversity and will by its nature respond very differently to treatment from person to person. To
meet the needs of this growing market, Biosource developed a technology to produce antigenic
material rapidly, in abundance, and in a form that will safely induce the appropriate immune
response.

``The study reported in PNAS demonstrated that our plant-based transient expression system
can produce soluble complex proteins that generate a strong and protective immune response,
and that it can produce the immunogenic protein faster than other technologies,'' said Robert
Erwin, CEO of Biosource Technologies. ``By integrating the protein expression capability with
high-throughput robotics, our newly created division, Biosource Antigenics, will provide leading
human and animal health vaccine companies with a preferred technology to rapidly prototype
their lead vaccine designs. Successful lead compounds can be produced by our clients and
partners or by our biomanufacturing division in Owensboro, Ky.''

Biosource Technologies, Inc., is a fully integrated research-through-manufacturing enterprise
which provides novel technologies to greatly improve the speed and productivity of life science
product development programs. In September, Biosource announced a three-year
collaboration with The Dow Chemical Company and Dow AgroSciences LLC to create one of
the world's largest plant functional genomic research programs dedicated to the discovery of
gene-based agricultural and chemical products. Biosource is headquartered in Vacaville, Calif.,
with manufacturing facilities in Owensboro, Ky. For more information about Biosource
Technologies, Inc., visit their web site at www.biosource-technologies.com.

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