Antigen-mediated regulation in monoclonal gammopathies and myeloma
Shiny Nair, … , Eric Meffre, Madhav V. Dhodapkar
Shiny Nair, … , Eric Meffre, Madhav V. Dhodapkar
Published April 19, 2018
Citation Information: JCI Insight. 2018;3(8):e98259. https://doi.org/10.1172/jci.insight.98259.
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Research Article Oncology

Antigen-mediated regulation in monoclonal gammopathies and myeloma

Abstract

A role for antigen-driven stimulation has been proposed in the pathogenesis of monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) based largely on the binding properties of monoclonal Ig. However, insights into antigen binding to clonal B cell receptors and in vivo responsiveness of the malignant clone to antigen-mediated stimulation are needed to understand the role of antigenic stimulation in tumor growth. Lysolipid-reactive clonal Ig were detected in Gaucher disease (GD) and some sporadic gammopathies. Here, we show that recombinant Ig (rIg) cloned from sort-purified single tumor cells from lipid-reactive sporadic and GD-associated gammopathy specifically bound lysolipids. Liposome sedimentation and binding assays confirmed specific interaction of lipid-reactive monoclonal Ig with lysolipids. The clonal nature of lysolipid-binding Ig was validated by protein sequencing. Gene expression profiling and cytogenetic analyses from 2 patient cohorts showed enrichment of nonhyperdiploid tumors in lipid-reactive patients. In vivo antigen-mediated stimulation led to an increase in clonal Ig and plasma cells (PCs) in GD gammopathy and also reactivated previously suppressed antigenically related nonclonal PCs. These data support a model wherein antigenic stimulation mediates an initial polyclonal phase, followed by evolution of monoclonal tumors enriched in nonhyperdiploid genomes, responsive to underlying antigen. Targeting underlying antigens may therefore prevent clinical MM.

Authors

Shiny Nair, Joel Sng, Chandra Sekhar Boddupalli, Anja Seckinger, Marta Chesi, Mariateresa Fulciniti, Lin Zhang, Navin Rauniyar, Michael Lopez, Natalia Neparidze, Terri Parker, Nikhil C. Munshi, Rachael Sexton, Bart Barlogie, Robert Orlowski, Leif Bergsagel, Dirk Hose, Richard A. Flavell, Pramod K. Mistry, Eric Meffre, Madhav V. Dhodapkar

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Figure 2

Binding of purified monoclonal Ig from lipid-reactive patients to GlcSph containing liposomes and C18 silica beads.

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Binding of purified monoclonal Ig from lipid-reactive patients to GlcSph...
(A) In the liposome sedimentation assay, purified monoclonal Ig (mIgs) from lipid-reactive sporadic MM patient were incubated with either control or GlcSph containing liposomes and, after centrifugation, separated into liposome-bound fraction (B; 100%) and liposome unbound fraction (S; 7.5%) and visualized using mIg-specific anti–human heavy chain antibody in immunoblots. (B) Binding of mIgs from lipid-reactive GD patient to GlcSph containing liposomes as determined by liposome sedimentation assay. (C) Lipid binding specificity of mIg was assessed in a liposome-binding assay using flow cytometry. Representative FACS profile shows the dose-dependent binding of FITC-labeled affinity purified mIg to GlcSph containing liposomes. Data from 1 representative patient is shown. (D) Binding of the FITC-labeled mIg from sporadic MM patient to GlcSph-coated C18 silica beads was assessed by flow cytometry (left). Bound clonal Ig was eluted using 1 M glycine (pH 2.0_, the beads were checked after elution by FACS, while the eluted fraction was visualized by immunoblotting (right). (E) Clonal Ig from lipid-reactive GD patient also show binding to GlcSph-coated C18 silica beads. (F) Percent quenching of the relative fluorescence intensity of NBD-GlcSph in NBD-GlcSph/cholesterol liposomes induced by GlcSph binding of mIg from lipid-reactive patient. No fluorescence quenching of NBD-cholesterol control liposome is observed in the presence of mIg. Data represent mean ± SEM. Data is representative of 4 similar experiments.