Isolation of monomeric human VHS by a phage selection

Human V-H domains are promising molecules in applications involving antibodies, in particular, immunotherapy because of their human origin. However, they are, in general, prone to aggregation. Therefore, various strategies have been employed to acquire monomeric human V(H)s. We had previously discovered that filamentous phages displaying engineered monomeric VH domains gave rise to significantly larger plaques on bacterial lawns than phages displaying wild type VHs with aggregation tendencies. Using plaque size as the selection criterion and a phage-displayed naive human VH library we identified 15 V(H)s that were monomeric. Additionally, the VHs demonstrated good expression yields, good refolding properties following thermal denaturation, resistance to aggregation during long incubation at 37 C, and to trypsin at 37 C. These 15 VHs should serve as good scaffolds for developing immunotherapeutics, and the selection method employed here should have general utility for isolating proteins with desirable biophysical properties.