Discovering and producing conditionally active biologic proteins in the same eukaryotic cell production hosts

A method of producing a conditionally active biologic protein, the method comprising:

• i. selecting a wild-type biologic protein;
• ii. evolving the DNA which encodes the wild-type biologic protein using one or more evolutionary techniques to create mutant DNAs;
• iii. expressing the mutant DNAs in a eukaryotic cell production host to obtain mutant proteins;
• iv. subjecting the mutant proteins and the wild-type protein to an assay under a normal physiological condition and to an assay under an aberrant condition;
• v. selecting a conditionally active biologic protein from the mutant proteins expressed in step (iii) which exhibit at least one of:
• (a) a decrease in activity in the assay at the normal physiological condition compared to the wild-type protein, and (b) an increase in activity in the assay under the aberrant condition compared to the wild-type protein;
• and
• vi. producing the conditionally active biologic protein in the same eukaryotic cell production host as used in step (iii).