October 9, 2007

Eggs from transgenic chickens to provide human antibodies

Eggs from transgenic chickens may soon be reared to provide humans with antibodies against certain strains of bacteria.

Origen Therapeutics in the US has been awarded a US$2 million in a three-year grant from the National Institute of Standards and Technology (NIST) to find out how it could be done.

Transgenic chickens are used as its cells can be activated with an antigen such as Staphylococcus aureus to produce human antibodies that can bind to the bacteria.

The company has developed the technology for inserting genetic modifications into the chicken genome, which involves removing or inactivating the genes that encode for chicken antibodies and in their place inserting gene sequences for human polyclonal antibodies.

The modifications are carried out in cell cultures of chicken primordial germ cells. These genetically modified cells are then injected into the developing vascular system of an early stage chicken embryo.

The company would soon apply the technology to insert human antibody sequences into the chicken and then to test and verify that the human sequence antibodies are produced as expected.

Found in the egg yolk, the antibodies will be extracted from the eggs produced by the transgenic chickens. Steps are then taken to collect the pure antibody.

These can be collected at levels of about 200mg per egg.

Origen estimates that if 100mg is collected per egg, a flock of 3,500 hens will produce approximately 75kg of antibody per year.