First Mabs Produced in Chickens

The antibodies produced in this manner demonstrated a 10-100 fold greater cell-killing ability, compared to therapeutic antibodies produced by conventional cell culture methods.

The antibodies were expressed solely in the chick oviduct and deposited into egg white in concentrations of 1-3 mg per egg. The achievement was the work of researchers from Texas A&M University (College Station, USA), the University of California, Los Angeles (USA), Origen Therapeutics (Burlinggame, CA, USA), and Medarex (Princeton, NJ, USA). The research was reported in the September 2005 issue of Nature Medicine.

To create the antibody-producing chickens, the researchers first inserted into chicken embryonic stem cells the genes encoding the antibody and the regulatory sequences restricting its deposition to egg white. The stem cells were then introduced into chick embryos. At that stage, the embryonic stem cells can make significant contributions to the developing chicken. Resulting chimeras with large contributions from the stem cells lay eggs containing milligram amounts of antibody, which is then separated from the egg white proteins generating the purified product.

"We expect the demand for more potent anticancer monoclonal antibodies and for lower production costs to increase at a rate that will tax existing cell-culture production systems,” observed Dr. Robert Etches, Ph.D., D.Sc., vice president, Origen Therapeutics. "Furthermore, unlike other transgenic animal systems, the time from antibody identification to production in eggs can be as short as eight months, versus 18 months to three years for goats or cattle. The egg is sterile and stable, providing a good starting material for isolation and purification of the protein of interest. Moreover, conditions for good manufacturing practices have been long-established for vaccine production in chicken eggs.”




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