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MuSK myasthenia gravis monoclonal antibodies: Valency dictates pathogenicity.
Huijbers, Maartje G; Vergoossen, Dana L; Fillié-Grijpma, Yvonne E; van Es, Inge E; Koning, Marvyn T; Slot, Linda M; Veelken, Hendrik; Plomp, Jaap J; van der Maarel, Silvère M; Verschuuren, Jan J.
Afiliação
  • Huijbers MG; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • Vergoossen DL; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • Fillié-Grijpma YE; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • van Es IE; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • Koning MT; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • Slot LM; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • Veelken H; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • Plomp JJ; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • van der Maarel SM; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
  • Verschuuren JJ; Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands.
Neurol Neuroimmunol Neuroinflamm ; 6(3): e547, 2019 05.
Article em En | MEDLINE | ID: mdl-30882021
ABSTRACT

Objective:

To isolate and characterize muscle-specific kinase (MuSK) monoclonal antibodies from patients with MuSK myasthenia gravis (MG) on a genetic and functional level.

Methods:

We generated recombinant MuSK antibodies from patient-derived clonal MuSK-specific B cells and produced monovalent Fab fragments from them. Both the antibodies and Fab fragments were tested for their effects on neural agrin-induced MuSK phosphorylation and acetylcholine receptor (AChR) clustering in myotube cultures.

Results:

The isolated MuSK monoclonal antibody sequences included IgG1, IgG3, and IgG4 that had undergone high levels of affinity maturation, consistent with antigenic selection. We confirmed their specificity for the MuSK Ig-like 1 domain and binding to neuromuscular junctions. Monovalent MuSK Fab, mimicking functionally monovalent MuSK MG patient Fab-arm exchanged serum IgG4, abolished agrin-induced MuSK phosphorylation and AChR clustering. Surprisingly, bivalent monospecific MuSK antibodies instead activated MuSK phosphorylation and partially induced AChR clustering, independent of agrin.

Conclusions:

Patient-derived MuSK antibodies can act either as MuSK agonist or MuSK antagonist, depending on the number of MuSK binding sites. Functional monovalency, induced by Fab-arm exchange in patient serum, makes MuSK IgG4 antibodies pathogenic.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Autoanticorpos / Receptores Colinérgicos / Receptores Proteína Tirosina Quinases / Anticorpos Monoclonais / Miastenia Gravis Idioma: En Ano de publicação: 2019 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Autoanticorpos / Receptores Colinérgicos / Receptores Proteína Tirosina Quinases / Anticorpos Monoclonais / Miastenia Gravis Idioma: En Ano de publicação: 2019 Tipo de documento: Article