Targeted fusion of Antibody-Secreting Cells: unlocking monoclonal antibody production with hybridoma technology

Abstract

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 TACIhighCD138high 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.