University of Colorado Denver
Principal Investigator: Dr. Jeffrey Bennett
Project Title: Second-Generation Aquaporumabs and NMO Superantibodies for NMO Research and Therapy
The generation of recombinant monoclonal antibodies (rAb) against aquaporin-4 has provided major new opportunities in NMO research and therapeutics. As NMO-rAbs are monoclonal and pure, they have afforded the ability to study NMO pathogenesis mechanisms in the absence of confounding serum factors in order to: (i) measure antibody targeting and pharmacokinetics in animal models; (ii) identify binding epitopes on AQP4; (iii) screen for small-molecule blockers; and (iv) develop aquaporumab blocking antibodies.
The NMO-rAbs generated to date are derived from sequencing clonally expanded plasma blasts in CSF of NMO patients. NMO-rAbs are fully human antibodies. The two NMO-rAbs with highest affinity for binding to AQP4 have dissociation constants of ~15 and 40 nM. Mutations of the Fc region of the antibody have generated antibodies with greatly reduced, though non-zero, CDC and/or ADCC effector functions. The intended use of these ‘aquaporumabs’ is for NMO therapy. Other mutations of the Fc region have generated antibodies with increased (by >10-fold) CDC or ADCC effector function. The intended use of these ‘NMO superantibodies’ is to generate animal models of NMO, which are badly needed to study NMO pathogenesis mechanisms and to develop new therapies.
The major goal of this research is to carry out screening/mutagenesis to produce second-generation aquaporumabs and NMO superantibodies. It has become evident that improvements in the AQP4 binding portion (Fab) and effector function (Fc) region of NMO-rAbs is needed. For aquaporumab therapy, an optimal antibody should have AQP4 binding dissociation constant ~ 0.1-0.5 nM and zero residual effector function. Very tight AQP4 binding affinity is also desired for generation of animal models with NMO superantibodies, as is greatly enhanced (>25-fold) effector function. It is anticipated that, with additional screening / affinity maturation / mutagenesis, NMO-rAbs with the target properties can be generated.
UC Denver NMO Team