Fig. 5.

Screening and expression of IgGs with selected HCs. (a) IgGs from the selection were expressed on small scale (30 µl) in cell-free extract and screened by ELISA to find leads that were specific for CEA over HER2/ErbB2, streptavidin and a PBS control. Positive controls show that an anti-CEA scFv-Fc is specific for CEA and the trastuzumab IgG is specific for HER2/ErbB2. Experiments performed on separate days are presented in separate charts. (b) A non-reducing SDS–PAGE gel shows significant expression of each selected IgG at the correct molecular weight for the fully assembled product. Proteins are labeled with ¹⁴C-Leu. (c) A reducing SDS–PAGE gel shows good expression of the majority of the reformatted complete HC and LC. Proteins are labeled with ¹⁴C-Leu. A ¹⁴C-labeled protein ladder (in kDa) is shown on the left lanes of the gels in (b) and (c).