Oostindie et al. applied “AND-gate” logic to eliminate malignant cells expressing two target molecules while sparing healthy cells expressing one or neither. Modifying anti-CD52 and -CD20 mAbs in their Fc regions enhanced hetero-hexamerization (increased cell-surface mAb proximity via FRET) and decoupled individual mAb–target binding from effector functions (FcγR and C1q binding). The mAbs in combination, but not individually, were selectively cytotoxic to CD52+CD20+ B cells and tumor lines, without affecting CD52+ T cells in vitro or in humanized NSG mice. This approach was flexibly applied to additional antibody combinations and for enhancing agonism.
Contributed by Alex Najibi
ABSTRACT: The use of therapeutic monoclonal antibodies is constrained because single antigen targets often do not provide sufficient selectivity to distinguish diseased from healthy tissues. We present HexElect(®), an approach to enhance the functional selectivity of therapeutic antibodies by making their activity dependent on clustering after binding to two different antigens expressed on the same target cell. lmmunoglobulin G (lgG)-mediated clustering of membrane receptors naturally occurs on cell surfaces to trigger complement- or cell-mediated effector functions or to initiate intracellular signaling. We engineer the Fc domains of two different lgG antibodies to suppress their individual homo-oligomerization while promoting their pairwise hetero-oligomerization after binding co-expressed antigens. We show that recruitment of complement component C1q to these hetero-oligomers leads to clustering-dependent activation of effector functions such as complement mediated killing of target cells or activation of cell surface receptors. HexElect allows selective antibody activity on target cells expressing unique, potentially unexplored combinations of surface antigens.
Author Info: (1) Genmab, Utrecht, the Netherlands. Department of Immunology, Leiden University Medical Center, Leiden, the Netherlands. (2) Department of Pathology, University of New Mexico Sch
Author Info: (1) Genmab, Utrecht, the Netherlands. Department of Immunology, Leiden University Medical Center, Leiden, the Netherlands. (2) Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM, USA. (3) Genmab, Utrecht, the Netherlands. (4) Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA. (5) Genmab, Utrecht, the Netherlands. (6) Genmab, Utrecht, the Netherlands. (7) Genmab, Utrecht, the Netherlands. (8) Genmab, Utrecht, the Netherlands. (9) Genmab, Utrecht, the Netherlands. (10) Genmab, Utrecht, the Netherlands. (11) Genmab, Utrecht, the Netherlands. (12) Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM, USA. (13) Genmab, Utrecht, the Netherlands. (14) Genmab, Utrecht, the Netherlands. (15) Genmab, Utrecht, the Netherlands. (16) Genmab, Utrecht, the Netherlands. (17) Genmab, Utrecht, the Netherlands. (18) Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM, USA. Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA. (19) Genmab, Utrecht, the Netherlands. (20) Genmab, Utrecht, the Netherlands. rjo@genmab.com.
