The invention relates to a method of identifying a desired antigen-binding agent that binds to an antigen of interest. The method utilizes a combinatorial approach wherein a nucleic acid sequence encoding a polypeptide comprising a first component of an antigen-binding agent is provided to a population of cells together with a library of nucleic acid sequences, each of which encodes a polypeptide comprising a second component of an antigen-binding agent. The method further comprises subjecting one or more of the nucleic acid sequences encoding a first component, a second component, and/or an identified antigen-binding agent to somatic hypermutation.
