Brent Cornell

      
Biopharming involves using transgenic plants or animals to produce (or ‘farm’) pharmaceutical products for therapeutic use

• This involves the insertion of target genes into hosts (crops or animals) that would not normally express those genes
• The desired compound can potentially be expressed in a form that is routinely harvested (e.g. milk, eggs, fruits, etc.)

There are several established examples of biopharming, including:

• Transgenic sheep that produce human α-1-antitrypsin in their milk (individuals deficient in this enzyme develop emphysema)
• Crops that express attenuated antigenic fragments for specific pathogenic diseases (i.e. edible vaccines) 

      
Antithrombin is a blood protein which inactivates certain enzymes in the coagulation system to prevent excessive clotting

• Individuals with a genetic or acquired antithrombin deficiency are at an increased risk of developing damaging blood clots

Genetically engineered antithrombin has been biopharmed from transgenic goats to produce stocks for commercial use

• A human gene encoding for antithrombin is introduced into the fertilised egg of a goat
• The modified eggs are implanted into the uterus of surrogates, which give birth to transgenic offspring
• The transgenic offspring will produce human antithrombin in its milk, which can then be extracted and purified
• Each year, the transgenic goat can produce a quantity of antithrombin equivalent to 90,000 human blood donations

Biopharming of Antithrombin