Patent ID: 7179592

Claim:
A method of screening a sample of complex biological material for an affinity ligand that binds to a protein target, comprising: (1) mixing a protein target and a sample of complex biological material in solution to form a reaction mixture; (2) incubating the reaction mixture wider conditions allowing complex formation by the target and any target-binding ligand present in the sample; (3) passing the reaction mixture through a first size-exclusion medium that removes from the reaction mixture any small molecular weight compounds each having a molecular weight less than a first preset value; (4) subjecting the size-excluded reaction mixture from step (3) to conditions promoting dissociation of any ligand/target complex into free ligand and free target; and (5) passing the reaction mixture resulting from step (4) through a second size exclusion medium that removes from the reaction mixture any molecule larger than a second preset value.