Re:5 years. at least. (Score 1)

However, a good fraction of the cost in making such proteins is the purification, not the initial production...In this age of avian influenza, we'd have to develop ways to test for avian viruses and a way to test for residual egg proteins in the purified drug

First off let me just say that separation of proteins is a rather standard thing in biochemistry there are a myriad of ways to do it probably the easiest and most widely used, atleast in biochemistry labs, is HPLC http://en.wikipedia.org/wiki/HPLC/. The ability to separate things is also incredibly dependant on the concentration of protein in the egg whites if they weren't getting a ton of protein it just wouldn't be worthwhile anyway. Also if you don't believe me perhaps a quote from TFA

The proteins are secreted into the whites of the eggs. It is a fairly straightforward process then to extract and purify them.

Also if you read the article and knew a bit of biochemistry you would know that post-translational modification doesn't really apply here because as stated in the article they are getting the protiens they want not modified ones. So thanks for throwing around Biochem buzzwords but seriously RTFA and try and get your facts straight.