Functional activity of anti-LINGO-1 antibody opicinumab requires target engagement at a secondary binding site. Issue 1 (1st January 2020)

• Record Type: Journal Article
• Authors: Hanf, Karl J. M.; Arndt, Joseph W.; Liu, YuTing; Gong, Bang Jian; Rushe, Mia; Sopko, Richelle; Massol, Ramiro; Smith, Benjamin; Gao, Yan; Dalkilic-Liddle, Isin; Lee, Xinhua; Mojta, Shanell; Shao, Zhaohui; Mi, Sha; Pepinsky, R. Blake
• Is Part Of: MAbs. Volume 12:Issue 1(2020)
• Publication Date: 2020-01-01
• Subjects: LINGO-1 -- anti-LINGO-1 antibody -- opicinumab -- multiple sclerosis -- oligodendrocyte -- remyelination -- internalization -- therapeutic antibody -- antibody engineering -- cryptic site -- mechanism of action; Monoclonal antibodies -- Therapeutic use -- Periodicals; Monoclonal antibodies -- Periodicals; Antibodies, Monoclonal -- Periodicals; 616.0798
• DOI: 10.1080/19420862.2020.1713648
• Languages: English
• ISSNs: 1942-0862

Abstract

ABSTRACT: LINGO-1 is a membrane protein of the central nervous system (CNS) that suppresses myelination of axons. Preclinical studies have revealed that blockade of LINGO-1 function leads to CNS repair in demyelinating animal models. The anti-LINGO-1 antibody Li81 (opicinumab), which blocks LINGO-1 function and shows robust remyelinating activity in animal models, is currently being investigated in a Phase 2 clinical trial as a potential treatment for individuals with relapsing forms of multiple sclerosis (AFFINITY: clinical trial.gov number NCT03222973). Li81 has the unusual feature that it contains two LINGO-1 binding sites: a classical site utilizing its complementarity-determining regions and a cryptic secondary site involving Li81 light chain framework residues that recruits a second LINGO-1 molecule only after engagement of the primary binding site. Concurrent binding at both sites leads to formation of a 2:2 complex of LINGO-1 with the Li81 antigen-binding fragment, and higher order complexes with intact Li81 antibody. To elucidate the role of the secondary binding site, we designed a series of Li81 variant constructs that eliminate it while retaining the classic site contacts. These Li81 mutants retained the high affinity binding to LINGO-1, but lost the antibody-induced oligodendrocyte progenitor cell (OPC) differentiation activity and myelination activity in OPC- dorsal root ganglion neuron cocultures seen with Li81. The mutations also attenuate antibody-induced internalization of LINGO-1 on cultured cortical neurons, OPCs, and cells over-expressing LINGO-1. Together these studies reveal that engagement at both LINGO-1 binding sites of Li81 is critical for robust functional activity of the antibody.