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.
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Authors | Karl J M Hanf, Joseph W Arndt, YuTing Liu, Bang Jian Gong, Mia Rushe, Richelle Sopko, Ramiro Massol, Benjamin Smith, Yan Gao, Isin Dalkilic-Liddle, Xinhua Lee, Shanell Mojta, Zhaohui Shao, Sha Mi, R Blake Pepinsky |
Journal | mAbs
(MAbs)
2020 Jan-Dec
Vol. 12
Issue 1
Pg. 1713648
ISSN: 1942-0870 [Electronic] United States |
PMID | 31928294
(Publication Type: Journal Article)
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Chemical References |
- Antibodies, Monoclonal
- LINGO1 protein, human
- Membrane Proteins
- Nerve Tissue Proteins
- opicinumab
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Topics |
- Antibodies, Monoclonal
(immunology)
- Binding Sites, Antibody
(immunology)
- Humans
- Membrane Proteins
(antagonists & inhibitors, immunology)
- Nerve Tissue Proteins
(antagonists & inhibitors, immunology)
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