Clonal Immortalized Mesenchymal Stromal Cells: An ideal cell source for a reproducible and standardized production of therapeutic extracellular vesicles

Within the last decade, we and others have successfully demonstrated the therapeutic efficacy of extracellular vesicles (EVs) prepared from the conditioned media of primary mesenchymal stromal cells (MSCs). Among others, our MSC-EV preparations suppressed disease symptoms of a treatment-resistant graft-versus-host disease (GvHD) patient and improved the outcomes in ischemic stroke and hypoxia-induced neonatal encephalopathy (HIE) animals notably.

Nevertheless, the considerable variability among donors and the limited lifespan of primary MSCs in vitro present substantial obstacles in translating primary MSC products successfully into the market.

To tackle this challenge, we have devised strategies addressing standardization, reproducibility, and scalability in EV production. Specifically, we have developed methods to immortalize primary MSCs and to successfully establish monoclonal MSC lines. Cells of resulting clonal immortalized MSC lines (ciMSCs) maintain their authentic and healthy bona fide MSC characteristics and still allow manufacturing of therapeutically active EV products.

Up to now, we have confirmed in various in vivo and in vitro assays that ciMSC-EVs conserved their function. Among others like their counterparts obtained from primary MSCs, they can suppress T cell activation in a multi-donor mixed lymphocyte reaction assay in a reproducible and standardized manner. Additionally, these ciMSC-EVs exhibit the ability to alleviate symptoms in ischemic stroke and HIE models, mirroring the efficacy of primary MSC-EVs.

Based on these findings, we conclude that ciMSC-EVs harbor therapeutic potentials, and ciMSCs represent an ideal cell source for the standardized, reproducible, and scalable manufacturing of EV-based therapeutics.

None