Engineering Soluble Recombinant BCMA for Ide‐Cel Labeling
Abstract
Chimeric antigen receptor (CAR)‐T‐based strategies target the B‐cell maturation antigen (BCMA) expressed on the surface of malignant plasma cells in patients with multiple myeloma (MM). Idecabtagene vicleucel (ide‐cel), an anti‐BCMA CAR‐T therapy, has shown promising results in the treatment of relapsed or refractory multiple myeloma (R/RMM). Notably, the extent of CAR‐T cell expansion correlates with objective response rates and complete responses, indicating that monitoring CAR‐T cells is critical for predicting clinical outcomes in these patients. Although several tools are available to monitor CAR‐T cells in patient blood samples, they remain costly, prompting us to develop novel fluorescent and soluble BCMA reagents for CAR‐T cell labeling. BCMA is a type III transmembrane protein, and we found that a recombinant construct consisting of the BCMA extracellular domain fused to green fluorescent protein (GFP) failed to traffic through the Golgi apparatus and was not secreted. Incorporation of the interferon‐α2 signal peptide restored intracellular trafficking and enabled efficient secretion of soluble BCMA‐GFP and BCMA‐mCherry fusion proteins. These reagents specifically labeled anti‐BCMA CAR‐T cells. Overall, our results establish a cost‐effective method to generate soluble BCMA probes and provide accessible tools for monitoring CAR‐T cells in translational settings.
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BibTeX
@article{nguyen2026engineering,
title = {{Engineering Soluble Recombinant BCMA for Ide‐Cel Labeling}},
author = {Ly Phuong Vy Nguyen and Christelle Oblet and Alice Barbarin and Louis Waeckel and Farah Kotaich and Clara Petit and Marine Mabily and Claire Carrion and André Herbelin and Jean-Marc Gombert and Xavier Leleu and Émilie Chalayer and Murielle Roussel and Patrick Legembre},
journal = {European Journal of Immunology},
year = {2026},
month = sep,
doi = {10.1002/eji.70251},
url = {https://hal.science/hal-05713720v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Engineering Soluble Recombinant BCMA for Ide‐Cel Labeling
AU - Ly Phuong Vy Nguyen
AU - Christelle Oblet
AU - Alice Barbarin
AU - Louis Waeckel
AU - Farah Kotaich
AU - Clara Petit
AU - Marine Mabily
AU - Claire Carrion
AU - André Herbelin
AU - Jean-Marc Gombert
AU - Xavier Leleu
AU - Émilie Chalayer
AU - Murielle Roussel
AU - Patrick Legembre
PY - 2026
DA - 2026/09/01
JO - European Journal of Immunology
DO - 10.1002/eji.70251
UR - https://hal.science/hal-05713720v1
AB - Chimeric antigen receptor (CAR)‐T‐based strategies target the B‐cell maturation antigen (BCMA) expressed on the surface of malignant plasma cells in patients with multiple myeloma (MM). Idecabtagene vicleucel (ide‐cel), an anti‐BCMA CAR‐T therapy, has shown promising results in the treatment of relapsed or refractory multiple myeloma (R/RMM). Notably, the extent of CAR‐T cell expansion correlates with objective response rates and complete responses, indicating that monitoring CAR‐T cells is critical for predicting clinical outcomes in these patients. Although several tools are available to monitor CAR‐T cells in patient blood samples, they remain costly, prompting us to develop novel fluorescent and soluble BCMA reagents for CAR‐T cell labeling. BCMA is a type III transmembrane protein, and we found that a recombinant construct consisting of the BCMA extracellular domain fused to green fluorescent protein (GFP) failed to traffic through the Golgi apparatus and was not secreted. Incorporation of the interferon‐α2 signal peptide restored intracellular trafficking and enabled efficient secretion of soluble BCMA‐GFP and BCMA‐mCherry fusion proteins. These reagents specifically labeled anti‐BCMA CAR‐T cells. Overall, our results establish a cost‐effective method to generate soluble BCMA probes and provide accessible tools for monitoring CAR‐T cells in translational settings.
SN - 0014-2980
SN - 1521-4141
ER -