Table 5.

Advantages and Disadvantages of Transgenic Expression in the Milk of Dairy Animals

Advantages High level expression at multigram/liter level Expression directed to and located in mammary gland Expression can be tested in rodents Genetic and lactation-to-lactation stability Animal-to-animal consistency Mammary epithelial cells carry out post-translational modification Product recovered at high concentration in milk Aseptic milk processing technology well proven Bulk impurities removed easily Low cost of pre-purification product Low investment costs Capability of combining transgenics with nuclear transfer (cloning) Disadvantages Possible adventitious virus and prion issues in dairy animals Control of animal environment and feed Microinjection required as a technology for species where cloning is not yet available Time to clinical product slower than cell culture (without process development)