The α v β 6 integrin is up-regulated in cancer and wound healing but it is not generally expressed in healthy adult tissue. There is increasing evidence that it has a role in cancer progression and will be a useful target for antibody-directed cancer therapies. We report a novel recombinant diabody antibody fragment that targets specifically α v β 6 and blocks its function. The diabody was engineered with a C-terminal hexahistidine tag (His tag), expressed in Pichia pastoris and purified by IMAC. Surface plasmon resonance (SPR) analysis of the purified diabody showed affinity in the nanomolar range. Pre-treatment of α v β 6 -expressing cells with the diabody resulted in a reduction of cell migration and adhesion to LAP, demonstrating biological function-blocking activity. After radio-labeling, using the His-tag for site-specific attachment of 99m Tc, the diabody retained affinity and targeted specifically to α v β 6 -expressing tumors in mice bearing isogenic α v β 6 +/- xenografts. Furthermore, the diabody was specifically internalized into α v β 6 -expressing cells, indicating warhead targeting potential. Our results indicate that the new α v β 6 diabody has a range of potential applications in imaging, function blocking or targeted delivery/internalization of therapeutic agents. © 2013 Kogelberg et al.
Kogelberg, H., Miranda, E., Burnet, J., Ellison, D., Tolner, B., Foster, J., … Chester, K. (2013). Generation and Characterization of a Diabody Targeting the α v β 6 Integrin. PLoS ONE, 8(9). https://doi.org/10.1371/journal.pone.0073260