Parameters affecting the display of antibodies on phage.

Despite the fact that a multitude of antibody phage display libraries has been built, systematic comparisons of critical design parameters are rare. Here we analysed the impact of various factors on the performance of the phage display system. First, we compared several vector designs for the display of Fab fragments of antibodies. Bicistronic as well as monocistronic expression of the antibody/pIII operon and vectors using fd-pIII as well as LC-pIII fusions were tested. Further, we evaluated the influence of glucose on the promoter induction. We compared monovalent versus oligovalent display of the antibody fragments and we used antibody fragments with different folding efficiency to assess the influence of the individual antibody sequences on the performance of the system. Finally, both phage display efficiency and yield of soluble Fab fragments were analysed. The significant differences found for phage yield, display of Fabs on the phage and expression of soluble Fabs suggest to use a bicistronic vector with an fd-fragment-pIII fusion for the construction of future Fab phage display libraries.