Rousseau, F.; Menier, C.; Brochard, P.; Simon, S.; Perez Toralla, K.; Wijkhuisen, A.

Monoclonal antibodies (mAbs) produced by hybridoma technology have extensively proved their value for therapeutic, diagnostic, and biomedical research applications, despite the reported low fusion yields between short-lived B cells and immortal myeloma cells. To improve the efficiency of this process and accelerate the development of new mAbs, we characterized and isolated antibody-secreting cells (ASCs) from the spleen of immunized mice before cell fusion. This approach resulted in a high yield of hybridoma generation by increasing the probability of successive pairing between the most suitable cell fusion partners. Specifically, we developed an optimized workflow combining Fluorescence-Activated Cell Sorting (FACS) with antibody secretion assays, using a panel of five cell-surface markers (CD3, TACI, CD138, MHC-II, and B220) that allowed us to identify a particular ASC subset with key characteristics. Such ASCs exhibited a plasmablast phenotype with high MHC-II expression and secreted high levels of Ag-specific antibodies in immunized mice. These features were also found in hybridomas, suggesting a preferential fusion of myeloma cells with this ASCs subset. Finally, the targeted electrofusion of TACI-high and CD138-high sorted ASCs led to a 100% fusion yield compared to a non-targeted approach. In particular, over 60% of these generated hybridomas secreted Ag-specific mAbs. Collectively, these results pave the way for a highly efficient method to produce new mAbs by cell fusion, which could facilitate hybridoma generation and expand therapeutic applications of mAbs.