Christian Doppler Laboratory for Antibody Engineering - Modul 2

In Module 2 of the CD-Laboratory for Antibody Engineering, two attractive applications of Modular Antibody Technology to improve Fab fragments will be investigated. Fab fragments are of limited clinical use today, due to their inherent short half-lives on the one hand and due to the fact that they do not display effector functions on the other hand. Both these issues will be addressed. A prolonged half-life can be engineered into proteins by endowing them with a binding site directed to a protein that already has a long half-life, such as serum albumin. CL / CH1 heterodimers with albumin binding sites engineered into the structural loops of the CL domain will be selected from yeast display libraries, characterized in vitro for their binding properties and subsequently tested for their in vivo half-life in mice. In the attempt to engineer the ability to display effector functions into Fab fragments, CL domains with binding sites specific to FcgammaR receptors such as FcgammaRIII will be selected from yeast display libraries. In order to test whether the selected engineered Fabs can actually elicit ADCC, they will be characterized both in vitro (binding to polymorphonuclear (PMN) cells and to natural killer (NK) cells; IL-2 and IFN-gamma production assays; in vitro ADCC tests) and, at a later stage also in in vivo in mouse tumor models.