3. Pathogen testing and elimination:

Transgenic animal source materials have the potential to contain a variety of human pathogens (e.g., viruses, bacteria, mycoplasma, and transmissible spongiform encephalopathy agents). Analytical methods and purification processes should be standardized to ensure the safety of the product. After consulting with veterinarians and other experts in the field, a specific list of pathogenic agents and accepted testing methods should be prepared and prioritized with regard to the risk of human infection. In cases where recombinant DNA was introduced by viral vector administration, or similar methods, the possibility of viral load in the product should be monitored.

6-4.3.4 Analysis of product identity and purity:

Before initiating studies in humans, the product from the transgenic source material should be characterized with respect to activity, safety, purity, and potency. Product similarities (e.g., potency, pharmacokinetics) and differences (e.g., glycosylation, antigenicity) with well characterized natural or recombinant molecules should also be performed.

Biochemical identity, purity and potency:

Physicochemical, immunological and biological characterizations should be carried out on the transgene product to assess its identity, purity and activity which include chemical structure, amino acid composition, disulfide linkages etc. The anatomical site of production in the transgenic animal may differ from the natural site of production and result in biochemical modifications that affect the activity of biological product.

Product heterogeneity:

Variations in final product activity should be examined with respect to variables associated with maintaining the transgenic herd and generating source material. For example, the identification of any variation in product structure, purity or activity when the source material is obtained: a) from different animals, b) during different seasons, c) from animals facing other sources of stress, d) from source material that has been stored for extended periods of time etc should be ascertained.